Counters series K176, K561. We understand the operating principle of K176IE4 K176IE4 in digital information display devices

We understand the operating principle of K176IE4. In this article I want to talk about the principle of working with K176IE4 - an indispensable driver for seven-segment indicators. I propose to analyze his work using the example of this circuit: Don’t be alarmed - although the circuit looks massive, despite this it is very simple, only 29 electronic components are used. The principle of operation of the K176IE4: The K176IE4 is inherently a very easy-to-understand microcircuit. It is a decimal counter with a decoder for a seven-segment display. It has 3 signal inputs and 9 signal outputs. Rated supply voltage - from 8.55 to 9.45V. The maximum current per output is 4mA. The inputs are: Clock line (4 leg of the microcircuit) - a signal comes through it, which causes the microcircuit to switch its states, that is, read Selecting a common anode/cathode (6 leg) - by connecting this line to the minus we can control the indicator with a common cathode, to the plus - with a common anode Reset (5th leg) - when applying log. 1 resets the counter to zero, when applying log. 0 - allows the microcircuit to switch states Outputs: 7 outputs to a seven-segment indicator (1, 8-13 legs) Clock signal divided by 4 (3 legs) - needed for clock circuits, we do not use Clock signal divided by 10 (2 legs) - allows combine several K176IE4, expanding the range of digits (you can add tens, hundreds, etc.) The counting principle works in such a way that when we switch the signal on the clock line from the log. 0 to log. 1 the current value increases by one The principle of operation of this circuit: To simplify the perception of the operation of this circuit, you can create the following sequence: NE555 produces a rectangular pulse K176IE4, under the influence of a pulse, increases its state by one Its current state is transmitted to the transistor assembly ULN2004 for amplification Boosted signal arrives at the LEDs The indicator displays the current state This circuit switches the states of IE4 once per second (this period of time is formed by an RC circuit consisting of R1, R2 and C2) NE555 can be easily replaced with KR1006VI1 C3 can be selected in the range from 10 to 100nF An amplifier is required since the maximum current per IE4 output is 4mA, and the rated current of most LEDs is 20mA. Any seven-segment indicators with a common anode and a rated voltage from 1.8 to 2.5V, with a current from 10 to 30mA are suitable. We connect the 6th leg of the microcircuit to the power supply minus, but at In this case, we use an indicator with a common anode, this is due to the fact that ULN2004 not only amplifies, but also inverts the signal. The microcircuit resets its state when power is applied (made by a circuit of C4 and R4) or by pressing a button (S1 and R3). Resetting when power is applied is necessary because, otherwise, the microcircuit will not work normally. A resistor in front of the reset button is necessary for safe operation of the button - almost all tact buttons are designed for a current of no more than 50mA, and therefore we must choose a resistor in the range of 9V/50mA=180Ohm and up to 1 kOhm Author: arssev1 Taken from http://cxem.net 20 pcs. NE555 NE555P NE555N 555 DIP-8 . US$0.99/lot

There are K176IE3 and K176IE4 microcircuits that contain a counter and a decoder designed to work with a seven-segment indicator. The microcircuits have the same pinouts and housings (shown in Figure 1A and 1B using the example of the K176IE4 microcircuit), the difference is that the K176IE3 counts up to 6, and the K176IE4 up to 10. Microcircuits are designed for electronic watch, so K176IE3 counts up to 6, for example, if you need to count tens of minutes or seconds.

In addition, both microcircuits have an additional output (pin 3). In the K176IE4 microcircuit, a unit appears on this pin at the moment when its counter goes into state “4”. And in the K176IE3 microcircuit, a unit appears on this pin at the moment when the counter counts to 2.
Thus, the presence of these pins makes it possible to build an hour counter that counts up to 24.

Consider the K176IE4 microcircuit (Figure 1A and 1B). Pulses are supplied to input “C” (pin 4), which the microcircuit must count and display their number in seven-segment form on a digital indicator. Input "R" (pin 5) is used to force the chip counter to zero. When a logical unit is applied to it, the counter goes into the zero state, and the indicator connected to the output of the chip’s decoder will show the number “0”, expressed in seven-segment form (see lesson No. 9).

The counter of the microcircuit has a carry output “P” (pin 2). The microcircuit counts up to 10 at this pin as a logical unit. As soon as the microcircuit reaches 10 (the tenth pulse arrives at its input “C”), it automatically returns to the zero state, and at this moment (between the fall of the 9th pulse and the edge of the 10th) a negative pulse is formed at the IR output ( zero difference).

The presence of this output "P" allows you to use the microcircuit as a frequency divider by 10, because the frequency of the pulses at this output will be 10 times lower than the frequency of the pulses arriving at the input "C" (every 10 pulses at the input "C" - by output "P" produces one pulse). But the main purpose of this output (IRI) is to organize a multi-digit counter.

Another input is “S” (pin 6), it is needed to select the type of indicator with which the microcircuit will work. If this led indicator with a common cathode (see lesson No. 9), then to work with it you need to apply a logical zero to this input. If the indicator has a common anode, you need to apply one.

Outputs "A-G" are used to control the segments of the LED indicator; they are connected to the corresponding inputs of the seven-segment indicator.

The K176IE3 chip works the same way as the K176IE4, but only counts up to 6, and a one appears on its pin 3 when its counter counts up to 2. Otherwise, the microcircuit is no different from K176IEZ.

Fig.2
To study the K176IE4 microcircuit, assemble the circuit shown in Figure 2. A pulse shaper is built on the D1 chip (K561LE5 or K176LE5). After each press and release of the S1 button, one pulse is generated at its output (at pin 3 of D1.1). These pulses arrive at input “C” of the D2 - K176IE4 chip. Button S2 serves to apply a single logic level to the input “R” of D2, thus moving the counter of the microcircuit to the zero position.

TO outputs A-G The D2 chip is connected to the H1 LED indicator. In this case, an indicator with a common anode is used, so for its segments to light up, the corresponding outputs D2 must have zeros. To switch the D2 chip to the operating mode with such indicators, one is applied to its input S (pin 6).

Using voltmeter P1 (tester, multimeter turned on in voltage measurement mode), you can observe the change in logical levels at the transfer output (pin 2) and at output “4” (pin 3).

Set chip D2 to zero state (press and release S2). The H1 indicator will show the number "0". Then, by pressing the S1 button, track the operation of the counter from “0” to “9”, and the next time it is pressed, it goes back to “0”. Then install the probe of the device P1 on pin 3 of D2 and press S1. At first, while counting from zero to three, this pin will show zero, but when the number “4” appears, this pin will show one (device P1 will show a voltage close to the supply voltage).

Try connecting pins 3 and 5 of the D2 chip to each other using a piece of mounting wire (shown with a dashed line in the diagram). Now the counter, having reached zero, will only count up to “4”. That is, the indicator readings will be “0”, “1”, “2”, “3” and again “0” and then in a circle. Pin 3 allows you to limit the chip count to four.

Fig.3
Install the probe of the device P1 to pin 2 of D2. The device will show one all the time, but after the 9th pulse, at the moment the 10th pulse arrives and goes to zero, the level here will drop to zero, and then, after the tenth, it will become unity again. Using this pin (output P), you can organize a multi-bit counter. Figure 3 shows the circuit of a two-digit counter built on two K176IE4 microcircuits. The pulses to the input of this counter come from the output of the multivibrator on elements D1.1 and D1.2 of the K561LE5 (or K176LE5) microcircuit.

The counter on D2 counts units of pulses, and after every ten pulses received at its input “C”, one pulse appears at its output “P”. The second counter - D3 counts these pulses (coming from the output "P" of counter D2) and its indicator shows dozens of pulses received at the input of D2 from the output of the multivibrator.

Thus, this two-digit counter counts from “00” to “99” and, with the arrival of the 100th pulse, goes to the zero position.

If we need this two-digit counter to count up to “39” (it goes to zero with the arrival of the 40th pulse), we need to connect pin 3 of D3 using a piece of mounting wire to pins 5 of both counters connected together. Now, with the end of the third ten input pulses, a unit from pin 3 of D3 will go to the “R” inputs of both counters and force them to zero.

Fig.4
To study the K176IE3 microcircuit, assemble the circuit shown in Figure 4. The circuit is the same as in Figure 2. The difference is that the microcircuit will count from “0” to “5”, and when the 6th pulse arrives, it will go to the zero state. A one will appear at pin 3 when the second pulse arrives at the input. The carry pulse at pin 2 will appear with the arrival of the 6th input pulse. While it counts up to 5 at pin 2 - one, with the arrival of the 6th pulse at the moment of transition to zero - a logical zero.

Using two microcircuits K176IE3 and K176IE4, you can build a counter, similar to what is used in electronic watches to count seconds or minutes, that is, a counter that counts up to 60. Figure 5 shows a diagram of such a counter. The circuit is the same as in Figure 3, but the difference is that K176IE3 is used as the D3 chip together with K176IE4.

Fig.5
And this microcircuit counts up to 6, which means the number of tens will be 6. The counter will count “00” to “59”, and with the arrival of the 60th pulse it will go to zero. If the resistance of resistor R1 is selected in such a way that the pulses at output D1.2 follow with a period of one second, then you can get a stopwatch that works up to one minute.

Using these microcircuits it is easy to build an electronic clock.

In this article I want to talk about the principle of working with K176IE4 - an indispensable driver for seven-segment indicators. I propose to analyze his work using this diagram as an example:

Don't be alarmed - although the circuit looks massive, despite this it is very simple, using only 29 electronic components

Operating principle of K176IE4:

K176IE4 is inherently a very easy-to-understand microcircuit. It is a decimal counter with a decoder for a seven-segment display. It has 3 signal inputs and 9 signal outputs.

Rated supply voltage - from 8.55 to 9.45V. Maximum current per output - 4mA

The inputs are:

• Clock line (4 pins of the microcircuit) - a signal comes through it, which causes the microcircuit to switch its states, that is, count
• Selecting a common anode/cathode (6 legs) - by connecting this line to the minus we can control the indicator with a common cathode, to the plus - with a common anode
• Reset (5th leg) - when filing log. 1 resets the counter to zero, when applying log. 0 - allows the chip to switch states

• 7 outputs per seven-segment indicator (1, 8-13 legs)
• Clock signal divided by 4 (3 legs) - needed for clock circuits, not used by us
• Clock signal divided by 10 (2 legs) - allows you to combine several K176IE4, expanding the range of digits (you can add tens, hundreds, etc.)

The counting principle works in such a way that when we switch the signal on the clock line from the log. 0 to log. 1 current value is increased by one

The operating principle of this scheme:

To simplify the understanding of the operation of this circuit, you can create the following sequence:

1. NE555 produces a square pulse
2. K176IE4 under the influence of an impulse increases its state by one
3. Its current state is transmitted to the ULN2004 transistor assembly for amplification
4. The amplified signal is sent to the LEDs
5. The indicator displays the current status

This circuit switches the states of IE4 once per second (this period of time is formed by an RC circuit consisting of R1, R2 and C2)

NE555 can be easily replaced with KR1006VI1

C3 can be selected in the range from 10 to 100nF

An amplifier is necessary since the maximum current per IE4 output is 4mA, and the rated current of most LEDs is 20mA

Seven-segment indicators are suitable for any with a common anode and a rated voltage from 1.8 to 2.5V, with a current from 10 to 30mA

We connect the 6th leg of the microcircuit to the minus of the power supply, but at the same time we use an indicator with a common anode, this is due to the fact that ULN2004 not only amplifies, but also inverts the signal

The microcircuit resets its state when power is applied (made by a circuit of C4 and R4) or when a button is pressed (S1 and R3). Resetting when power is applied is necessary because, otherwise, the microcircuit will not work normally

A resistor in front of the reset button is necessary for safe operation of the button - almost all tact buttons are designed for a current of no more than 50mA, and therefore we must choose a resistor in the range from 9V/50mA=180Ohm to 1kOhm

List of radioelements

The series of microcircuits under consideration includes a large number of counters various types, most of which work in weight codes.

The K176IE1 chip (Fig. 172) is a six-bit binary counter operating in code 1-2-4-8-16-32. The microcircuit has two inputs: input R - setting the counter triggers to 0 and input C - input for supplying counting pulses. Setting to 0 occurs when submitting a log. 1 to input R, switching the triggers of the microcircuit - according to the decline of pulses of positive polarity supplied to input C. When constructing

multi-bit frequency dividers, the inputs C of the microcircuits should be connected to the outputs of the 32 previous ones.

The K176IE2 chip (Fig. 173) is a five-bit counter that can operate as a binary counter in the 1-2-4-8-16 code when applying a log. 1 to control input A, or as a decade with a trigger connected to the output of the decade with a log. 0 at input A. In the second case, the counter operating code is 1-2-4-8-10, the total division coefficient is 20. Input R is used to set the counter triggers to 0 by applying a log to this input. 1. The first four counter triggers can be set to a single state by applying a log. 1 for inputs SI - S8. Inputs S1 - S8 are dominant over input R.

The K176IE2 microcircuit comes in two varieties. Early release microcircuits have CP and CN inputs for supplying clock pulses of positive and negative polarity, respectively, connected via OR. When pulses of positive polarity are applied to the CP input, the CN input must be log. 1, when pulses of negative polarity are applied to the CN input, there must be a log at the CP input. 0. In both cases, the counter switches according to pulse declines.

Another type has two equal inputs for supplying clock pulses (pins 2 and 3), collected via AND. Counting occurs based on the declines of pulses of positive polarity supplied to any of these inputs, and a log must be supplied to the second of these inputs. 1. Pulses can also be applied to the combined pins 2 and 3. The microcircuits studied by the author, released in February and November 1981, belong to the first type, released in June 1982 and June 1983, to the second.

If you apply a log to pin 3 of the K176IE2 chip. 1, both types of microcircuits at the CP input (pin 2) work the same.

At log. 0 at input A, the order of operation of the flip-flops corresponds to the timing diagram shown in Fig. 174. In this mode, at the output P, ​​which is the output of the AND-NOT element, the inputs of which are connected to outputs 1 and 8 of the counter, pulses of negative polarity are allocated, the edges of which coincide with the fall of every ninth input pulse, the fall - with the fall of every tenth.

When connecting K176IE2 microcircuits into a multi-bit counter, the CP inputs of subsequent microcircuits should be connected to outputs 8 or 16/10 directly, and a log should be applied to the CN inputs. 1. At the moment the supply voltage is turned on, the triggers of the K176IE2 microcircuit can be set to an arbitrary state. If the counter is switched to decimal counting mode, that is, a log is applied to input A. 0, and this state is more than 11, the counter “cycles” between states 12-13 or 14-15. In this case, pulses are formed at outputs 1 and P with a frequency that is 2 times less than the frequency of the input signal. In order to exit this mode, the counter must be set to the zero state by applying a pulse to input R. You can ensure reliable operation of the counter in decimal mode by connecting input A to output 4. Then, being in state 12 or higher, the counter switches to binary mode account and leaves the “forbidden zone”, setting after state 15 to zero. At the moments of transition from state 9 to state 10, a log is received at input A from output 4. 0 and the counter is reset to zero, operating in decimal counting mode.

To indicate the state of decades using the K176IE2 microcircuit, you can use gas-discharge indicators controlled through the K155ID1 decoder. To match the K155ID1 and K176IE2 microcircuits, you can use the K176PU-3 or K561PU4 microcircuits (Fig. 175, a) or pnp transistors (Fig. 175, b).

Microcircuits K176IE3 (Fig. 176), K176IE4 (Fig. 177) and K176IE5 are designed specifically for use in electronic watches with seven-segment indicators. Microcircuit K176IE4 (Fig. 177) is a decade with a counter code converter into a seven-segment indicator code. The microcircuit has three inputs - input R, the counter triggers are set to 0 when the log is applied. 1 to this input, input C - triggers switching occurs based on the decline of positive pulses

polarity at this input. The signal at the S input controls the polarity of the output signals.

At outputs a, b, c, d, e, f, g - output signals that ensure the formation of numbers on a seven-segment indicator corresponding to the state of the counter. When submitting log. 0 to control input S log. 1 at outputs a, b, c, d, e, f, g correspond to the inclusion of the corresponding segment. If you apply a log to the S input. 1, the inclusion of segments will correspond to log. 0 at outputs a, b, c, d, e, f, g. The ability to switch the polarity of output signals significantly expands the scope of application of microcircuits.

The output P of the microcircuit is the transfer output. The decline of a pulse of positive polarity at this output is formed at the moment the counter transitions from state 9 to state 0.

It should be borne in mind that the layout of pins a, b, c, d, e, f, g in the microcircuit data sheet and in some reference books is given for non-specific purposes. standard arrangement indicator segments. In Fig. 176, 177 shows the pinout for the standard arrangement of segments shown in Fig. 111.

Two options for connecting vacuum seven-segment indicators to the K176IE4 microcircuit using transistors are shown in Fig. 178. The filament voltage Uh is selected in accordance with the type of indicator used, selecting a voltage of +25...30 V in the circuit of Fig. 178 (a) and -15...20 V in the circuit of Fig. 178 (b) you can adjust the brightness of the indicator segments within certain limits. Transistors in the circuit Fig. 178 (6) can be any silicon pnp with a reverse collector junction current not exceeding 1 µA at a voltage of 25 V, If reverse current transistors are larger than the specified value or germanium transistors are used, 30...60 kOhm resistors must be connected between the anodes and one of the terminals of the indicator filament.

To coordinate the K176IE4 microcircuit with vacuum indicators, it is convenient, in addition, to use the K168KT2B or K168KT2V microcircuits (Fig. 179), as well as KR168KT2B.V, K190KT1, K190KT2, K161KN1, K161KN2. The connection of the K161KN1 and K161KN2 microcircuits is illustrated in Fig. 180. When using the K161KN1 inverting microcircuit, a log should be applied to the S input of the K176IE4 microcircuit. 1, when using a non-inverting microcircuit K161KN2 - log. 0.

In Fig. 181 shows options for connecting semiconductor indicators to the K176IE4 microcircuit; in Fig. 181 (a) with a common cathode, in Fig. 181 (b) - with a common anode. Resistors R1 - R7 set the required current through the indicator segments.

The smallest indicators can be connected to the outputs of the microcircuit directly (Fig. 181, c). However, due to the large current spread short circuit microcircuits, not standardized technical specifications, the brightness of the indicators may also vary widely. It can be partially compensated by selecting the supply voltage of the indicators.

To match the K176IE4 microcircuit with semiconductor indicators with a common anode, you can use the K176PU1, K176PU2, K176PU-3, K561PU4, KR1561PU4, K561LN2 microcircuits (Fig. 182). When using non-inverting microcircuits, a log should be applied to the S input of the microcircuit. 1, when using inverting ones - log. 0.

According to the diagram in Fig. 181 (b), excluding resistors R1 - R7, you can also connect filament indicators, while the supply voltage of the indicators must be set approximately 1 V more than the nominal one to compensate for the voltage drop across the transistors. This voltage can be either constant or pulsating, obtained as a result of rectification without filtering.

Liquid crystal indicators do not require special coordination, but to turn them on, you need a source of rectangular pulses with a frequency of 30–100 Hz and a duty cycle of 2; the amplitude of the pulses must correspond to the supply voltage of the microcircuits.

Pulses are applied simultaneously to the input S of the microcircuit and to the common electrode of the indicator (Fig. 183). As a result, a voltage of varying polarity is applied to the segments that need to be indicated relative to the common electrode of the indicator; on segments that do not need to be indicated, the voltage relative to the common electrode is zero

The K176IE-3 microcircuit (Fig. 176) differs from the K176IE4 in that its counter has a conversion factor of 6, and log 1 at output 2 appears when the counter is set to state 2.

The K176IE5 microcircuit contains a quartz oscillator with an external resonator at 32768 Hz and a nine-bit frequency divider and a six-bit frequency divider connected to it, the structure of the microcircuit is shown in Fig. 184 (a). resonator, resistors R1 and R2, capacitors C1 and C2 The output signal of the quartz oscillator can be monitored at outputs K and R A signal with a frequency of 32768 Hz is fed to the input of a nine-bit binary frequency divider, from its output 9 a signal with a frequency of 64 Hz can be fed to the input 10 of a six-bit divider At the output 14 of the fifth digit of this divider a frequency of 2 Hz is formed, at the output 15 of the sixth digit - 1 Hz. A signal with a frequency of 64 Hz can be used to connect liquid crystal indicators to the outputs of the K176IE- and K176IE4 microcircuits.

Input R is used to reset the triggers of the second divider and set the initial phase of oscillations at the outputs of the microcircuit. When submitting

log. 1 to input R at outputs 14 and 15 - log. 0, after removing log. 1, pulses with the corresponding frequency appear at these outputs, the decline of the first pulse at output 15 occurs 1 s after the log is removed. 1.

When submitting log. 1 to input S, all triggers of the second divider are set to state 1, after removing the log. 1 from this input, the decline of the first pulse at outputs 14 and 15 occurs almost immediately. Typically, the S input is permanently connected to the common wire.

Capacitors C1 and C2 are used to accurately set the frequency of the quartz oscillator. The capacity of the first of them can range from a few to one hundred picofarads, the capacity of the second - -0...100 pF. As the capacitance of the capacitors increases, the generation frequency decreases. It is more convenient to accurately set the frequency using tuning capacitors connected in parallel with C1 and C2. In this case, a capacitor connected in parallel with C2 performs a rough adjustment, while a capacitor connected in parallel with C1 performs a fine adjustment.

The resistance of resistor R 1 can be in the range of 4.7...68 MOhm, however, when its value is less than 10 MOhm, they are excited

not all quartz resonators.

Microcircuits K176IE8 and K561IE8 are decimal counters with a decoder (Fig. 185). The microcircuits have three inputs - installation input initial state R, input for supplying counting pulses of negative polarity CN and input for supplying counting pulses of positive polarity CP. The counter is set to 0 when the R log is applied to the input. 1, while a log appears at output 0. 1, at outputs 1-9 - log. 0.

The counter switches according to the declines of negative polarity pulses supplied to the CN input, while there must be a log at the CP input. 0. You can also apply pulses of positive polarity to the CP input; switching will occur based on their declines. There should be a log at the CN input. 1. The timing diagram of the microcircuit is shown in Fig. 186.

Microcircuit K561IE9 (Fig. 187) - a counter with a decoder, the operation of the microcircuit is similar to the operation of microcircuits K561IE8

and K176IE8, but the conversion factor and the number of decoder outputs are 8, not 10. The timing diagram of the microcircuit is shown in Fig. 188. Just like the K561IE8 microcircuit, the microcircuit:

K561IE9 is built on the basis of a shift register with cross connections. When supply voltage is applied and there is no reset pulse. The triggers of these microcircuits can become in an arbitrary state that does not correspond to the allowed state of the counter. However, in these microcircuits there is a special circuit for forming the allowed state of the counter, and when clock pulses are applied, the counter will switch to normal operating mode after a few clock cycles. Therefore, in frequency dividers in which the exact phase of the output signal is not important, it is permissible not to supply initial setting pulses to the R inputs of the K176IE8, K561IE8 and K561IE9 microcircuits.

Microcircuits K176IE8, K561IE8, K561IE9 can be combined into multi-bit counters with serial carry by connecting the carry output P of the previous chip with the CN input of the next one and applying a log to the CP input. 0. It is also possible to connect the older one

decoder output (7 or 9) with the CP input of the next microcircuit and fed to the CN input log. 1. Such connection methods lead to the accumulation of delays in a multi-bit counter. If it is necessary for the output signals of multi-bit counter microcircuits to change simultaneously, parallel carry should be used with the introduction of additional NAND elements. In Fig. 189 shows the circuit of a three-decade parallel carry counter. Inverter DD1.1 is needed only to compensate for delays in elements DD1.2 and DD1.3. If high accuracy of simultaneous switching of decades of the counter is not required, the input counting pulses can be applied to the CP input of the DD2 microcircuit without an inverter, and to the CN input of DD2 - logic 1. The maximum operating frequency of multi-bit counters with both serial and parallel transfer does not decrease relative to the operating frequency of a separate microcircuit.

In Fig. 190 shows a fragment of a timer circuit using K176IE8 or K561IE8 microcircuits. At the moment of start-up, counting pulses begin to arrive at the CN input of the DD1 microcircuit. When the counter chips are installed in the positions set on the switches, logs will appear at all inputs of the NAND element DD3. 1, element

DD3 will turn on, a log will appear at the output of inverter DD4. 1, signaling the end of the time interval.

Microcircuits K561IE8 and K561IE9 are convenient to use in frequency dividers with a switchable division coefficient. In Fig. 191 shows an example of a three-decade frequency divider. Switch SA1 sets the units of the required conversion factor, switch SA2 - tens, switch SA3 - hundreds. When counters DD1 - DD3 reach a state corresponding to the switch positions, a log is sent to all inputs of element DD4.1. 1. This element turns on and sets the trigger on elements DD4.2 and DD4.3 to a state in which a log appears at the output of element DD4.3. 1, resetting counters DD1 - DD3 to their original state (Fig. 192). As a result, a log also appears at the output of element DD4.1. 1 and the next input pulse of negative polarity sets the trigger DD4.2, DD4.3 to its initial state, the reset signal from the R inputs of microcircuits DD1 - DD3 is removed and the counter continues counting.

The trigger on elements DD4.2 and DD4.3 guarantees the reset of all microcircuits DD1 - DD3 when the counter reaches the desired state. In its absence and a large spread of microcircuit switching thresholds

DD1 - DD3 by inputs R, it is possible that one of the microcircuits DD1 - DD3 is set to 0 and removes the reset signal from the R inputs of the remaining microcircuits before the reset signal reaches their switching threshold. However, such a case is unlikely, and usually you can do without a trigger, more precisely, without the DD4.2 element.

To obtain a conversion factor of less than 10 for the K561IE8 microcircuit and less than 8 for the K561IE9, you can connect the decoder output with a number corresponding to the required conversion factor to the R input of the microcircuit directly, for example, as shown in Fig. 193(a) for a conversion factor of 6. Temporary

A diagram of the operation of this divider is shown in Fig. 193(6). The carryover signal can be removed from output P only if the conversion factor is 6 or more for K561IE8 and 5 or more for K561IE9. For any coefficient, the transfer signal can be removed from the output of the decoder with a number one less than the conversion factor.

It is convenient to indicate the status of the counters of the K176IE8 and K561IE8 microcircuits using gas-discharge indicators, coordinating them using keys on high-voltage n-p-n transistors, for example, series P307 - P309, KT604, KT605 or K166NT1 assemblies (Fig. 194).

Microcircuits K561IE10 and KR1561IE10 (Fig. 195) contain two separate four-bit binary counters, each of which has inputs CP, CN, R. The counter triggers are set to their initial state when a log is applied to the R input. 1. The operating logic of the CP and CN inputs is different from the operation of similar inputs of the K561IE8 and K561IE9 microcircuits. Triggers of the K561IE10 and KR561IE10 microcircuits are triggered by the decline of pulses of positive polarity at the CP input at log. 0 at the CN input (for K561IE8 and K561IE9 the CN input must be logic 1) It is possible to supply negative polarity pulses to the CN input, while the CP input must be log 1 (for K561IE8 and K561IE9 - logic 0). Thus, the CP and CN inputs in the K561IE10 and KR1561IE10 microcircuits are combined according to the AND element circuit, in the K561IE8 and K561IE9 microcircuits - OR.

A timing diagram of the operation of one microcircuit counter is shown in Fig. 196. When connecting microcircuits into a multi-bit counter with serial transfer, the outputs of 8 previous counters are connected to the CP inputs of subsequent ones, and a log is supplied to the CN inputs. 0 (Fig. 197). If it is necessary to provide parallel transfer, additional AND-NOT and NOR elements should be installed. In Fig. 198 shows a diagram of a counter with parallel carry. The passage of the counting pulse to the input of the CP counter DD2.2 through the element DD1.2 is allowed in state 1111 of the counter DD2.1, in which the output of the element DD3.1 is logical. 0. Similarly, the passage of a counting pulse to the input of the CP DD4.1 is possible only in the state of 1111 counters DD2.1 and DD2.2, etc. The purpose of element DD1.1 is the same as DD1.1 in the circuit of Fig. 189, and under the same conditions it can be excluded. The maximum frequency of input pulses for both counter options is the same, but in a counter with parallel transfer, all output signals are switched simultaneously.

One counter of the microcircuit can be used to construct frequency dividers with a division factor from 2 to 16. For example, in Fig. 199 shows a diagram of a counter with a conversion factor of 10. To obtain conversion factors -, 5, 6, 9, 12, you can use the same diagram, appropriately selecting the counter outputs for connection to the inputs DD2.1 To obtain conversion factors 7, 11, 13, l4 element DD2.1 must have three inputs, for coefficient 15 - four inputs.

The K561IE11 chip is a binary four-bit up/down counter with the possibility of parallel recording of information (Fig. 200). The microcircuit has four information outputs 1, 2, 4,8, a transfer output P and the following inputs: a transfer input PI, an input for setting the initial state R, an input for supplying counting pulses C, a counting direction input U, inputs for supplying information during parallel recording Dl - D8, parallel recording input S.

Input R has priority over other inputs: if a log is applied to it. 1, outputs 1, 2, 4, 8 will be log.0 regardless of the state

other entrances. If the input R is log. 0, input S has priority. When a log is applied to it. 1, information is asynchronously written from inputs D1 - D8 to the counter triggers.

If the inputs R, S, PI are log. 0, the microcircuit is allowed to operate in counting mode. If at the input U log. 1, for each decline in the input pulse of negative polarity arriving at input C, the counter state will increase by one. At log. 0 at input U the counter switches

In subtraction mode - for each decline of a pulse of negative polarity at input C, the counter state decreases by one. If you apply a log to the PI transfer input. 1, counting mode is prohibited.

At the transfer output P log. 0 if the PI input is log. 0 and all counter flip-flops are at state 1 when counting up or at state 0 when counting down.

To connect microcircuits into a counter with serial transfer, it is necessary to combine all the C inputs, connect the P outputs of the next microcircuits to the PI inputs of the next ones, and apply a log to the PI input of the low-order digit. 0 (Fig. 201). The output signals of all counter chips change simultaneously, but the maximum operating frequency of the counter is less than that of an individual chip due to the accumulation of delays in the transfer circuit. To ensure the maximum operating frequency of a multi-bit counter, it is necessary to provide parallel transfer, for which a log is applied to the PI inputs of all microcircuits. Oh, and apply signals to the inputs C of the microcircuits through additional OR elements, as shown in Fig. 202. In this case, the passage of the counting pulse to the inputs C of the microcircuits will be allowed only when there is a log at the outputs P of all previous microcircuits. 0,

Moreover, the delay time of this resolution after the simultaneous operation of the microcircuits does not depend on the number of digits of the counter.

The design features of the K561IE11 microcircuit require that the change in the counting direction signal at the U input occur in the pause between the counting pulses at the C input, that is, at log. 1 at this input, or on the decline of this pulse.

The K176IE12 chip is intended for use in electronic watches (Fig. 203). It consists of a quartz oscillator G with an external quartz resonator at a frequency of 32768 Hz and two frequency dividers: ST2 at 32768 and ST60 at 60. When connected to a quartz resonator microcircuit according to the diagram in Fig. 203 (b) it provides frequencies of 32768, 1024, 128, 2, 1, 1/60 Hz. Pulses with a frequency of 128 Hz are formed at the outputs of the T1 - T4 microcircuit, their duty cycle is 4, they are shifted among themselves by a quarter of a period. These pulses are designed to switch the familiarity of the clock indicator during dynamic display. 1/60 Hz pulses are applied to the minute counter, 1 Hz pulses can be used to feed the seconds counter and cause the dividing point to flash, and 2 Hz pulses can be used to set the hour. The frequency of 1024 Hz is intended for the sound alarm signal and for interrogating the digits of counters during dynamic display, the frequency output of 32768 Hz is the control one. The phase relationships of oscillations of various frequencies relative to the moment the reset signal is removed are shown in Fig. 204, the time scales of the various diagrams in this figure are different. Using

pulses from outputs T1 - T4 for other purposes, you should pay attention to the presence of short false pulses at these outputs.

A feature of the microcircuit is that the first drop in the output of the minute pulses M appears 59 s after the 0 setting signal is removed from the R input. This forces the button generating the 0 setting signal to be released when starting the clock, one second after the sixth time verification signal. The rises and falls of the signals at the output M are synchronous with the falls of pulses of negative polarity at the input C.

The resistance of resistor R1 can have the same value as for the K176IE5 microcircuit. Capacitor C2 is used for fine frequency adjustment, C- for coarse frequency adjustment. In most cases, capacitor C4 can be omitted.

The K176IE13 microcircuit is intended for building an electronic clock with an alarm clock. It contains minute and hour counters, an alarm clock memory register, comparison circuits and sound signal output, and dynamic output circuits for digit codes for feeding to indicators. Usually the K176IE13 chip is used in conjunction with the K176IE12. The standard connection of these microcircuits is shown in Fig. 205. The main output signals of the circuit in Fig. 205 are pulses T1 - T4 and digital codes at outputs 1, 2, 4, 8. At times when the output T1 is log. 1, at outputs 1,2,4,8 there is a code for the digit of units of minutes, when log. 1 at output T2 - code for tens of minutes, etc. At output S - pulses with a frequency of 1 Hz to ignite the dividing point. Pulses at output C are used to strobe the recording of digit codes in the memory register of microcircuits K176ID2 or K176ID-, usually used in conjunction with K176IE12 and K176IE13; the pulse at output K can be used to extinguish indicators during clock correction. It is necessary to extinguish the indicators, since at the moment of correction the dynamic indication stops and, in the absence of extinguishing, only one digit lights up with four times the brightness.

The HS output is the alarm clock output signal. The use of outputs S, K, HS is optional. Log feed 0 to the V input of the microcircuit puts its outputs 1, 2, 4, 8 and C into a high-impedance state.

When power is applied to the microcircuits, zeros are automatically written to the hour and minute counter and the alarm clock memory register. To enter the initial reading into the minute counter, press

button SB1, the counter readings will begin to change with a frequency of 2 Hz from 00 to 59 and then 00 again, at the moment of transition from 59 to 00 the hour counter readings will increase by one. The hour counter will also change at a frequency of 2 Hz from 00 to 23 and again 00 if you press the SB2 button. If you press the SB3 button, the alarm time will appear on the indicators. When you press the SB1 and SB3 buttons simultaneously, the display of the minute digits of the alarm clock time will change from 00 to 59 and again 00, but the transfer to the hour digits does not occur. If you press the SB2 and SB3 buttons, the indication of the hour digits of the alarm clock time will change; when moving from state 23 to 00, the minute digits will be reset. You can press three buttons at once, in this case the readings of both the minute and hour digits will change.

Button SB4 is used to start the clock and correct the rate during operation. If you press the SB4 button and release it one second after the sixth time signal, the correct reading and the exact operating phase of the minute counter will be established. Now you can set the hour counter by pressing the SB2 button, without disturbing the minute counter. If the minute counter readings are in the range 00...39, the hour counter readings will not change when pressing and releasing the SB4 button. If the minute counter readings are in the range of 40...59, after releasing the SB4 button, the hour counter readings increase by one. Thus, to correct the clock, regardless of whether the clock was late or in a hurry, it is enough to press the SB4 button and release it a second after the sixth time signal.

The standard scheme for turning on the time setting buttons has the disadvantage that if you accidentally press the SB1 or SB2 buttons, the clock readings will fail. If in the diagram Fig. 205 add one diode and one button (Fig. 206), the clock readings can be changed only by pressing two buttons at once - the SB5 button ("Set-

ka") and the SB1 or SB2 button, which is much less likely to be done accidentally.

If the clock readings and the alarm time do not coincide, the HS output of the K176IE13 chip is log. 0. If the readings coincide, pulses of positive polarity appear at the HS output with a frequency of 128 Hz and a duration of 488 μs (duty factor 16). When fed through an emitter follower to any emitter, the signal resembles the sound of a conventional mechanical alarm clock. The signal stops when the readings of the clock and the alarm clock no longer coincide.

The scheme for matching the outputs of the K176IE12 and K176IE13 microcircuits with indicators depends on their type. For example in Fig. 207 shows a diagram for connecting semiconductor seven-segment indicators with a common anode. Both cathode (VT12 - VT18) and anode (VT6, VT7, VT9, VT10) switches are made according to emitter follower circuits. Resistors R4 - R10 determine the pulse current through the indicator segments.

Indicated in Fig. 207, the value of the resistances of resistors R4 -R10 provides a pulse current through the segment of approximately 36 mA, which corresponds to an average current of 9 mA. At this current, the indicators AL305A, ALS321B, ALS324B and others have a fairly bright glow. The maximum collector current of transistors VT12 - VT18 corresponds to a current of one segment of 36 mA and therefore here you can use almost any low-power pnp transistors with a permissible collector current of 36 mA or more.

The pulse currents of the transistors of the anode switches can reach 7 x 36 - 252 mA, therefore, transistors that allow the specified current can be used as anode switches, with a base current transfer coefficient h21e of at least 120 (KT3117, KT503, KT815 series).

If transistors with such a coefficient cannot be selected, you can use composite transistors (KT315 + KT503 or KT315 + KT502). Transistor VT8 - any low-power, n-p-n structure.

Transistors VT5 and VT11 are emitter repeaters for connecting the alarm clock sound emitter HA1, which can be used as any telephone, including small ones from hearing aids, or any dynamic heads connected through an output transformer from any radio receiver. By selecting the capacitance of capacitor C1, you can achieve the required signal volume, you can also set variable resistor 200...680 Ohm, turning it on with a potentiometer between C1 and HA1. Switch SA6 is used to turn off the alarm signal.

If indicators with a common cathode are used, the emitter followers connected to the outputs of the DD3 microcircuit should be made using n-p-n transistors (KT315 series, etc.), and the S input of DD3 should be connected to the common wire. To supply pulses to cathodes. indicators, switches should be assembled on n-p-n transistors according to a circuit with a common emitter. Their bases should be connected to outputs T1 - T4 of the DD1 microcircuit through 3.3 kOhm resistors. The requirements for transistors are the same as for transistors of anode switches in the case of indicators with a common anode.

Indication is also possible using luminescent indicators. In this case, it is necessary to supply pulses T1 - T4 to the indicator grids and connect interconnected indicator anodes of the same name through the K176ID2 or K176ID- microcircuit to outputs 1, 2, 4, 8 of the K176IE13 microcircuit.

The diagram for supplying pulses to the indicator grids is shown in Fig. 208. Grids C1, C2, C4, C5 - respectively, grids of familiarity of units and tens of minutes, units and tens of hours, C- - grid of the dividing point. The indicator anodes should be connected to the outputs of the K176ID2 microcircuit connected to DD2 in accordance with the inclusion of DD3 in Fig. 207 using keys similar to the keys in Fig. 178 (b), 179,180, a log must be applied to the S input of the K176ID2 microcircuit. 1.

It is possible to use the K176ID-chip without keys; its S input must be connected to the common wire. In any case, the anodes and grids of indicators must be connected through resistors 22...100 kOhm to a source of negative voltage, which in absolute value is 5...10 V greater than the negative voltage supplied to the cathodes of the indicators. In the diagram Fig. 208 are resistors R8 - R12 and voltage -27 V.

It is convenient to supply pulses T1 - T4 to the indicator grids using the K161KN2 microcircuit, applying supply voltage to it in accordance with Fig. 180.

Any single-place vacuum luminescent indicators, as well as flat four-place indicators with dividing points IVL1 - 7/5 and IVL2 - 7/5, specially designed for watches, can be used as indicators. As a DD4 circuit in Fig. 208, any inverting logic elements with combined inputs can be used.

In Fig. 209 shows a scheme for matching with gas-discharge indicators. Anode switches can be made on transistors of the KT604 or KT605 series, as well as on transistors of K166NT1 assemblies.

The HG5 neon lamp serves to indicate the dividing point. The indicator cathodes of the same name should be combined and connected to the outputs of the DD7 decoder. To simplify the circuit, you can eliminate the DD4 inverter, which ensures that the indicators are turned off while the correction button is pressed.

The ability to transfer the outputs of the K176IE13 microcircuit to a high-impedance state allows you to build a clock with two reading options (for example, MSK and GMT) and two alarms, one of which can be used to turn on a device, the other to turn it off (Fig. 210).

The same-name inputs of the main DD2 and additional DD2 of the K176IE13 microcircuits are connected to each other and to other elements according to the diagram in Fig. 205 (possible taking into account Fig. 206), with the exception of inputs P and V. In the upper position of the switch SA1 according to the diagram, the signals

settings from buttons SB1 - SB3 can be sent to the P input of the DD2 chip, in the lower one - to DD2. The supply of signals to the DD3 chip is controlled by section SA1.2 of the switch. In the upper position of switch SA1 log. 1 is supplied to input V of microcircuit DD2 and signals from the outputs of DD2 pass to the inputs of DD3. In the lower position of the switch, log. 1 at the V input of the DD2 chip allows the transmission of signals from its outputs.

As a result, when switch SA1 is in the upper position, you can control the first clock and alarm clock and indicate their status, and in the lower position, the second one.

Triggering of the first alarm turns on the trigger DD4.1, DD4.2, a log appears at the output of DD4.2. 1, which can be used to turn on a device; the second alarm turns off that device. Buttons SB5 and SB6 can also be used to turn it on and off.

When using two K176IE13 microcircuits, the reset signal to the R input of the DD1 microcircuit should be taken directly from the SB4 button. In this case, the readings are corrected as in the case shown in Fig. 205 connection, but blocking the SB4 "Corr."

when you press the button SB3 "Bud." (Fig. 205), which exists in the standard version, does not occur. When buttons SB3 and SB4 are pressed simultaneously in a watch with two K176IE13 microcircuits, the readings fail, but not the clock movement. Correct readings are restored if you press the SB4 button again while SB3 is released.

Chip K561IE14 - binary and binary decimal four-digit decimal counter (Fig. 211). Its difference from the K561IE11 microcircuit lies in the replacement of input R with input B - the switching input of the counting module. At log. 1 at input B, the K561IE14 microcircuit produces binary counting, just like the K561IE11, with a log. 0 at input B - binary decimal. The purpose of the remaining inputs, operating modes and switching rules for this microcircuit are the same as for the K561IE11.

KA561IE15 microcircuit is a frequency divider with a switchable division ratio (Fig. 212). The microcircuit has four control inputs Kl, K2, K-, L, an input for supplying clock pulses C, sixteen inputs for setting the division coefficient 1-8000 and one output.

The microcircuit allows you to have several options for setting the division coefficient, the range of its change is from 3 to 21327. Here we will consider the simplest and most convenient option, for which, however, the maximum possible division coefficient is 16659. For this option, the K- input should be constantly supplied log. 0.

Input K2 is used to set the initial state of the counter, which occurs over three periods of input pulses when a log is applied to input K2. 0. After filing log. 1 to input K2, the counter starts operating in frequency division mode. Frequency division coefficient when feeding log. 0 to inputs L and K1 is equal to 10000 and does not depend on the signals supplied to inputs 1-8000. If different input signals are applied to inputs L and K1 (log. 0 and logic 1 or logic 1 and logic 0), the frequency division factor of the input pulses is determined by the binary decimal code supplied to inputs 1-8000. For example in Fig. 213 shows a timing diagram of the operation of the microcircuit in the division by 5 mode, to ensure which a log should be applied to inputs 1 and 4. 1, to inputs 2, 8-8000 - log. 0 (K1 is not equal to L).

The duration of the output pulses of positive polarity is equal to the period of the input pulses, the rises and falls of the output pulses coincide with the fall of the input pulses of negative polarity.

As can be seen from the timing diagram, the first pulse at the output of the microcircuit appears on the decline of the input pulse with a number one greater than the division coefficient.

When submitting log. 1 to inputs L and K1, single counting mode is carried out. When applied to input K2 log. 0 at the output of the microcircuit a log appears. 0. The duration of the initial setting pulse at input K2 must be, as in the frequency division mode, at least three periods of input pulses. After the end of the initial setting pulse at input K2, counting will begin, which will occur according to the declines of the input pulses of negative polarity. After the end of a pulse with a number one greater than the code set at inputs 1-8000, log. 0 at the output will change to log. 1, after which it will not change (Fig. 213, K1 - L - 1). For the next start, it is necessary to again apply the initial setting pulse to input K2.

This mode of operation of the microcircuit is similar to the operation of a standby multivibrator with digital installation pulse duration, you should only remember that the duration of the input pulse includes the duration of the initial setting pulse and, in addition, another period of the input pulses.

If, after completing the formation of the output signal in single counting mode, a log is applied to input K1. 0, the microcircuit will switch to the input frequency division mode, and the phase of the output pulses will be determined by the initial setting pulse supplied earlier in the single-count mode. As mentioned above, the microcircuit can provide a fixed frequency division ratio of 10,000 if a log is applied to the L and K1 inputs. 0. However, after the initial setting pulse applied to input K2, the first output pulse will appear after a pulse with a number one unit greater than the code set at inputs 1-8000 is applied to input C. All subsequent output pulses will appear 10,000 periods of input pulses after the start of the previous one.

At inputs 1-8, permissible combinations of input signals must correspond to the binary equivalent of decimal numbers from 0 to 9. At inputs 10-8000, arbitrary combinations are permissible, that is, it is possible to supply codes of numbers from 0 to 15 to each decade. As a result, the maximum possible division coefficient K will be:

K - 15000 + 1500 + 150 + 9 = 16659.

The microcircuit can be used in frequency synthesizers, electric musical instruments, programmable time relays, for forming precise time intervals in the operation of various devices.

The K561IE16 chip is a fourteen-bit binary counter with serial transfer (Fig. 214). The microcircuit has two inputs - the input for setting the initial state R and the input for supplying clock pulses C. The counter triggers are set to 0 when a log is applied to the input R. 1, counting - according to the declines of pulses of positive polarity supplied to input C.

The counter does not have outputs of all bits - there are no outputs of bits 21 and 22, therefore, if it is necessary to have signals from all binary bits of the counter, you should use another counter that operates synchronously and has outputs 1, 2, 4, 8, for example half of the K561IE10 microcircuit ( Fig. 215).

The division coefficient of one K561IE16 microcircuit is 214 = 16384; if it is necessary to obtain a larger division coefficient, the output 213 of the microcircuit can be connected to the input of another similar microcircuit or to the CP input of any other microcircuit - a counter. If the input of the second K561IE16 microcircuit is connected to the output 2^10 of the previous one, it is possible, by reducing the counter's bit capacity, to obtain the missing outputs of the two bits of the second microcircuit (Fig. 216). By connecting half of the K561IE10 microcircuit to the input of the K561IE16 microcircuit, you can not only obtain the missing outputs, but also increase the counter's bit capacity by one (Fig. 217) and provide a division coefficient of 215 = 32768.

The K561IE16 microcircuit is convenient to use in frequency dividers with a tunable division coefficient according to a circuit similar to Fig. 199. In this circuit, element DD2.1 must have as many inputs as there are units in the binary representation of the number that determines the required division coefficient. For example in Fig. 218 shows a diagram of a frequency divider with a conversion factor of 10000. The binary equivalent of the decimal number 10000 is 10011100010000, an AND element is required for five inputs, which must be connected to the outputs 2^4=16.2^8 =256.2^9= 512.2 ^10=1024 and 2^13=8192. If you need to connect to outputs 2^2 or 2^3, you should use the diagram in Fig. 215 or 59, with a coefficient of more than 16384 - diagram in Fig. 216.

To convert a number into binary form, divide it completely by 2, and write down the remainder (0 or 1). Divide the resulting result by 2 again, write down the remainder, and so on until zero remains after the division. The first remainder is the least significant digit of the binary form of the number, the last is the most significant.

Chip K176IE17 - calendar. It contains counters for days of the week, days of the month and months. The number counter counts from 1 to 29, 30 or 31 depending on the month. The days of the week are counted from 1 to 7, the months are counted from 1 to 12. The connection diagram of the K176IE17 microcircuit to the K176IE13 clock chip is shown in Fig. 219. At outputs 1-8 of the DD2 microcircuit there are alternately codes for the digits of the day and month, similar to the codes for the hours and minutes at the outputs

K176IE13 microcircuits. Connecting indicators to the specified outputs of the K176IE17 microcircuit is carried out similarly to their connection to the outputs of the K176IE13 microcircuit using write pulses from output C of the K176IE13 microcircuit.

At outputs A, B, C there is always a code 1-2-4 of the serial number of the day of the week. It can be applied to the K176ID2 or K176ID- microcircuit and then to any seven-segment indicator, as a result of which the number of the day of the week will be displayed on it. However, more interesting is the possibility of displaying a two-letter designation of the day of the week on the alphanumeric indicators IV-4 or IV-17, for which it is necessary to make a special code converter.

Setting the date, month and day of the week is done in the same way as setting the readings in the K176IE13 microcircuit. When you press the SB1 button, the date is set, the SB2 button - the month, when you press SB3 and SB1 together - the day of the week. To reduce the total

number of buttons in a clock with a calendar, you can use buttons SB1 -SB3, SB5 diagrams in Fig. 206 to set the calendar readings, switching their common point with a toggle switch from the P input of the K176IE13 chip to the P input of the K176IE17 chip. For each of these microcircuits, the R1C1 circuit must be its own, similar to the circuit in Fig. 210.

Log feed 0 to the V input of the microcircuit puts its outputs 1-8 into a high-impedance state. This property of the microcircuit makes it relatively easy to organize alternating display of clock and calendar readings on one four-digit indicator (except for the day of the week). Scheme
connection of the K176ID2 (ID-3) microcircuit to the IE13 and IE17 microcircuits to ensure the specified mode is shown in Fig. 220, the circuits connecting the K176IE13, IE17 and IE12 microcircuits to each other are not shown. In the top position of the switch SA1 ("Clock"), outputs 1-8 of the DD3 microcircuit are in a high-impedance state, the output signals of the DD2 microcircuit through resistors R4 - R7 are supplied to the inputs of the DD4 microcircuit, the state of the DD2 microcircuit is indicated - hours and minutes. When the switch SA1 ("Calendar") is in the lower position, the outputs of the DD3 chip are activated, and now the DD3 chip determines the input signals of the DD4 chip. Transfer the outputs of the DD2 microcircuit to a high-impedance state, as is done in the circuit

rice. 210, it is impossible, since in this case the output C of the DD2 microcircuit will also go into a high-impedance state, and the DD3 microcircuit does not have a similar output. In the diagram of Fig. 220 implements the above-mentioned use of one set of buttons for setting the clock and calendar. Pulses from the SB1 - SB3 buttons are sent to the P input of the DD2 or DD3 chip, depending on the position of the same switch SA1.

The K176IE18 microcircuit (Fig. 221) is in many ways similar in structure to the K176IE12. Its main difference is the implementation of outputs T1 - T4 with an open drain, which allows you to connect grids of vacuum fluorescent indicators to this microcircuit without matching keys.

To ensure reliable locking of the indicators along their grids, the duty cycle of the T1 - T4 pulses in the K176IE18 microcircuit is made slightly more than four and is 32/7. When submitting log. 1 to input R of the microcircuit at outputs T1 - T4 log. 0, so supplying a special blanking signal to the K input of the K176ID2 and K176ID3 microcircuits is not required.

Vacuum fluorescent green indicators appear much brighter in the dark than in the light, so it is desirable to be able to change the brightness of the indicator. The K176IE18 microcircuit has a Q input, with a log feed. 1 to this input you can increase the duty cycle of pulses at outputs T1 - T4 and in

Decrease the brightness of the indicators the same number of times. The signal to input Q can be supplied either from a brightness switch or from a photoresistor, the second terminal of which is connected to the power positive. In this case, the Q input should be connected to the common wire through a 100 k0m...1 MOhm resistor, which must be selected to obtain the required external illumination threshold at which automatic switching brightness.

It should be noted that with log. 1 at input Q (low brightness) the clock setting has no effect.

The K176IE18 chip has a special audio signal generator. When a pulse of positive polarity is applied to the HS input, bursts of negative polarity pulses with a frequency of 2048 Hz and a duty cycle of 2 appear at the HS output. The duration of the bursts is 0.5 s, the repetition period is 1 s. The HS output is made with an open drain and allows you to connect emitters with a resistance of 50 Ohms and higher between this output and the power supply without an emitter follower. The signal is present at the HS output until the end of the next minute pulse at the M output of the microcircuit.

It should be noted that the permissible output current of the K176IE18 microcircuit at outputs T1 - T4 is 12 mA, which significantly exceeds the current of the K176IE12 microcircuit, therefore the requirements for the gain factors of transistors in the switches when using K176IE18 microcircuits and semiconductor indicators (Fig. 207) are much less stringent, quite h21e > 20. Basic resistance

Resistors in cathode switches can be reduced to 510 Ohms for h21e > 20 or to 1k0m for h21e > 40.

Microcircuits K176IE12, K176IE13, K176IE17, K176IB18 allow a supply voltage the same as the K561 series microcircuits - from 3 to 15 V.

The K561IE19 microcircuit is a five-bit shift register with the possibility of parallel recording of information, intended for constructing counters with a programmable counting module (Fig. 222). The chip has five information inputs for parallel recording D1 -D5, information input for sequential recording DO, parallel recording input S, reset input R, clock input C and five inverse outputs 1-5.

Input R is predominant - when a log is applied to it. 1 all Triggers of the microcircuit are set to 0, a log appears at all outputs. 1 regardless of signals at other inputs. When applied to the input R log. 0, to input S log. 1, information is written from inputs D1 - D5 to the triggers of the microcircuit; at outputs 1-5 it appears in inverse form.

When applied to inputs R and S log. 0, it is possible to shift information in the triggers of the microcircuit, which will occur according to the declines of negative polarity pulses arriving at input C. Information will be written to the first trigger from input D0.

If you connect the DO input to one of the outputs 1-5, you can get a counter with a conversion factor of 2, 4, 6, 8, 10. For example, in Fig. 223 shows a timing diagram of the operation of the microcircuit in the division by 6 mode, which is organized when input D0 is connected to output 3. If it is necessary to obtain an odd conversion factor of 3,5,7 or 9, you should use a two-input AND element, the inputs of which are connected respectively to outputs 1 and 2, 2 and 3, 3 and 4,4 and 5, output - to the DO input. For example in Fig. 224 shows a circuit of a frequency divider by 5, in Fig. 225 - timing diagram of its operation.

It should be borne in mind that using the K561IE19 microcircuit as a shift register is impossible, since it contains correction circuits, as a result of which combinations of trigger states that are not operational for the counting mode are automatically corrected. The presence of correction circuits allows

Similar to using the K561IE8 and K561IE9 microcircuits, do not supply an initial setting pulse to the counter if the phase of the output pulses is not important.

The KR1561IE20 microcircuit (Fig. 226) is a twelve-bit binary counter with division factors 2^12 = 4096. It has two inputs - R (for setting the zero state) and C (for supplying clock pulses). At log. 1 at input R the counter is set to zero, and when log. 0 - counts by the declines of pulses of positive polarity arriving at input C. The microcircuit can be used to divide the frequency into coefficients that are powers of 2. To build dividers with a different division coefficient, you can use a circuit to turn on the K561IE16 microcircuit (Fig. 218).

The KR1561IE21 microcircuit (Fig. 227) is a synchronous binary counter with the possibility of parallel recording of information on the decline of the clock pulse. The microcircuit functions similarly to K555IE10 (Fig. 38).

The counter diagram below is simplest example the use of K176IE4 microcircuits, which are decimal counters with a decoder.

A pulse generator for switching counters is created on the chip. Resistor R1 and capacitor C1 (mainly a resistor) set the pulse frequency. With elements such as those in the diagram, the frequency was 1.2 s.

K176IE4 – pulse counter with counter status output to a seven-segment indicator. It counts the impulses received at input C (4th leg). When these pulses fall, the counter switches. From the output “J” (3rd leg of the microcircuit), a frequency 4 times lower than the clock frequency is taken, and from the output “P” (2nd leg of the microcircuit), the frequency is 10 times lower than the clock frequency; the logical unit drops when the counter state transitions from “9” to "0". It is used to connect the next higher digit meter. Input R is used to reset the counters; it occurs when a logical one appears on it. It should be noted that if this input hangs in the air, not connected to anything, then the microcircuit most often perceives a unit there and does not count. To avoid this, it is necessary to pull it to ground, connecting it to the common negative through a 100 - 300 Ohm resistor, or directly if you do not plan to use the zeroing function. Input S is intended for switching operating modes of the microcircuit with different indicators. If this pin is connected to + power supply, then the microcircuit switches to operating mode with an indicator with a common anode; if from - power supply, then to operating mode with an indicator with a common cathode. Outputs 1, 8 – 13 are used to connect an indicator.

IC1 counts the 4 generator pulses received at its input; when it moves from 9 to 0, output 2 drops into a logical one, and IC2 switches up 1 value.

Key S1 controls the power, S2 resets the counters (I used a reed switch and a magnet instead).

The indicator requires a seven-segment two-digit indicator (or two seven-segment indicators). If the indicator has a common cathode (minus), then the legs of 6 K176IE4 microcircuits should be connected to ground, and if with a common anode (plus), then to the plus of the power source. The diagram is drawn for a common anode.

I also cite printed circuit board. I did not draw the indicator itself on it, since their pinouts are very different. Therefore, the reader will have to modify the board himself to fit his existing indicator. I also draw your attention to the fact that on the board there are 6 legs of microcircuits connected to + power supply, but if you have an indicator with a common “minus”, then you need to connect them to – power supply.

Parts List:

• microcircuit K176LE5 – 1 piece;
• microcircuit K176IE4 – 2 pieces;
• resistor 1 MOhm;
• resistor 220 Ohm;
• capacitor 220 nF.

That's all, the circuit basically does not require configuration.

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