Data sheet acquired from Harris Semiconductor. SCHSC − Revised October HCDB consists of an oscillator section and December CDBMS. CMOS 14 Stage Ripple-Carry Binary Counter/ Divider and Oscillator. DATASHEET. Pinout. Functional Diagram. HEF Datasheet, HEF PDF, HEF Data sheet, HEF manual, HEF pdf, HEF, datenblatt, Electronics HEF, alldatasheet, free.
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This is generally why high frequency devices avoid breadboards. The precision of the resistor value has no effect on the precision of the time base B. When the clock is switched to SET mode though, the SET line goes low, which keeps the reset line to the seconds counter constantly high, preventing the seconds counter to count.
This allows you to advance the hours counter. When the hours counter is reset, so is the flip-flop, making its Q output high.
We need 1Hz, not 2Hz, to feed to our seconds counter. TP1 is a hdf4060 point at which you can measure the buffered The Q output will be used by the display part of the circuit to suppress the leading 0 of the hours counter. The first problem is with the 16Mhz xtal the thing doesn’t even start to oscillate.
Breadboards add inductance to all the pins and force large loops in your wiring. That means a huge parasitic series inductance for 16MHz. This reset pulse is also used as carry to the hours counter. It uses a hef40600 Maybe this should be another question I tried with some random values, from 1 to pF, and nothing. Next stop, the minutes counter. Axeman 3, 14 Therefore IC9C will fatasheet follow the low going carry signal from the minutes counter.
It’s output Q0 of the first decade counter IC4A. Now IC9D will inverse the pulses coming from the push button. I don’t need the output of the seconds counter itself, because I do not have a seconds display.
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There’s one output we might use though. This will produce a high going reset pulse on the output of IC10B.
The other sheet covers the display circuit and the power supply. Now IC9D will inverse the pulses hef datasheet from the push button. Solderless breadboards are further limited by their voltage and current ratings. Problem is that I have fixed values on the output pins! IC2 forms hef datasheet time base oscillator and first pre-scaler stage. The Time Base IC2 forms the time base oscillator and first pre-scaler stage. The other sheet covers the display circuit and the power supply.
Moreover I don’t have the datasheet for the specific xtal, so I don’t know how to find right capacitor values. However that would require one extra chip for just one gate, whereas I had a spare flip-flop available which could be ab used for the hsf4060 job.
The oscillator part is built as described in the HEF data sheet.
This not only prevents the clock from advancing every minute during SET mode, it also starts counting a whole new minute once the clock is set to RUN mode again. So, the logic and Master Reset is working, but the counter is not. C5 is used to set the correct frequency. Together with this knowledge you should be able to build the clock yourself too. This counter is also formed by 2 decade counters.
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IC2 also contains a 14 bit divider chain. The Hours Counter And now the hours counter. This helps to tune the frequency of the time base to the correct value. This not only prevents the clock hdf advancing every minute during SET mode, it also starts counting a whole new minute once the hef datasheet is set to RUN mode again.
The precision of the resistor value has no effect on the precision of the time base B. Let’s start simple, the buttons, which are used to set the time.
They also make proper power bypassing difficult because you have to use caps with long leads. At the end it will produce an accurate frequency of 2Hz on output pin 3. The 16Mhz one still have some problem, because it starts to oscillate only if I remove the hef4006 between PIN11 and ground. Sign up using Facebook. The Wikipedia Page on them states pF per contact pointso you may have far datashet much capacitance on your crystal In Run mode only the SET button will have hef datasheet effect, the other 3 buttons are inhibited.
IC4B tries to do the same for the 0. This removes the breadboard from the connection entirely, and will likely be far more reliable.