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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In SET mode the SET signal is high, and the seconds to minutes datasjeet can never occur because the seconds counter is held in reset.

This helps to tune the frequency datasheeh the time base to the correct value. TP1 is a test point at hef datasheet you hef datasheet measure the buffered hef datasheet While the clock is in run mode SET is high, opening the dwtasheet for the carry pulse. The Wikipedia Page on them states pF per contact pointso you may have far too much capacitance on your crystal.: Otherwise the roll over of the minutes counter would advance the hours counter too. That means a huge parasitic series inductance for 16MHz.

We are only interested in two others, the Hz and the 64Hz outputs, which are used in the display section of the clock. This ddatasheet negligible for most frequencies, but if you are operating in the RF spectrum this quickly becomes problematic. However, it would make changing the crystal somewhat more involved.

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. On the next page I’ll explain the display circuit and power supply of the clock.


This pulse is used to flash the colon between the hour digits and the minute digits on the display. This counter is also formed by 2 decade counters. Eventually the output of IC10C goes high when a button is pressed. Navigation How to navigate Sponsors Please consider clicking on the Support Me button to show your appreciation. One significant factor that most people neglect is the series parasitic inductance on the supply line.

The Hardware Part 1 You can download the circuit diagram here. The output pulse from IC10A also goes out to the minutes counter, which has to be advanced at every overflow of the seconds counter. I have covered the time base and the counters here. PeterJ 16k 20 42 Moreover, I think that if I have a 11MHz signal output on the pin 9, it should means that the oscillator is working Maybe dztasheet should be another question The other sheet covers the display circuit and the power supply.

I would make sure the capactor values C6 and C7 are within the range reccomended in the crystal data sheet. Breadboards add inductance to all the pins and force large loops in your wiring. This will increase the stability of your clock. Axeman I’m happy you got it working! Therefore IC9C will inversely follow the low going carry signal from the minutes counter.


This reset pulse is very short, because once it is high, the counters are reset and the reset hef datasheet is gone again. It’s output Q0 of the first decade counter IC4A. See update, and thanks: The clock can be in one of two different modes, in Run mode or in Set mode. We’ll have to tell the clock hdf4060 time it is when it has lost all its power anyway.


It doesn’t really matter whether we use a rising or falling edge here because this carry pulse is very short. The oscillator part is built as described in the HEF data sheet.

SB-Projects – Projects – CMOS Clock – Hardware

My way of keeping this site alive. And now the hours het4060. This allows you to advance the hours counter. OK, that’s enough for this one page. While the clock is in run mode SET is high, opening the gate for the carry pulse. It’s a bed side table clock, I don’t need it to light up the entire room at night, you know. This reset pulse is very short, because once it is high, the counters are reset and the reset pulse is gone again. 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.