Hi,
I am currently working on a project to design and build a BCD clock. I managed to obtain an old book called "Discovering Electronic Clocks - W. D. Phillips" which is very useful.
To start with I am looking at the basic clock design in chapter six. This uses a 32.768KHz crystal, a few capacitors and resistors, a 4060 counter and 4013 flip flop to generate a 1Hz signal. After this a 1Hz 64Hz and 2048Hz signal is fed into a channel selector and three buttons: "Allow", "Slow" and "Fast" are used to set the time. I feel that this arrangement isn't the most elegant because the clock can't be set accurately. The 1Hz signal is used to clock 6 cascaded decade counters (4518s - two in each package) and then these feed some 4511 7-segment display drivers.
My intention initially is to replace the channel selector with a 40106 Schmitt Inverter to de-bounce three switches. One to reset the seconds, one to clock the minutes and one to clock the hours. All is fine with the seconds reset and the hours and minutes clock buttons work... but only when the seconds or minutes are outside of 40 - 59 seconds, because of the way that the 4518s are wired.
Unfortunately my software won't simulate the crystal properly, so I am taking out the channel selector and 4060 for the time being and just injecting a 1Hz signal from the software.
Please see the attached diagram.
Looking forward to any comments or suggestions.
Kind Regards
Edward
I am currently working on a project to design and build a BCD clock. I managed to obtain an old book called "Discovering Electronic Clocks - W. D. Phillips" which is very useful.
To start with I am looking at the basic clock design in chapter six. This uses a 32.768KHz crystal, a few capacitors and resistors, a 4060 counter and 4013 flip flop to generate a 1Hz signal. After this a 1Hz 64Hz and 2048Hz signal is fed into a channel selector and three buttons: "Allow", "Slow" and "Fast" are used to set the time. I feel that this arrangement isn't the most elegant because the clock can't be set accurately. The 1Hz signal is used to clock 6 cascaded decade counters (4518s - two in each package) and then these feed some 4511 7-segment display drivers.
My intention initially is to replace the channel selector with a 40106 Schmitt Inverter to de-bounce three switches. One to reset the seconds, one to clock the minutes and one to clock the hours. All is fine with the seconds reset and the hours and minutes clock buttons work... but only when the seconds or minutes are outside of 40 - 59 seconds, because of the way that the 4518s are wired.
Unfortunately my software won't simulate the crystal properly, so I am taking out the channel selector and 4060 for the time being and just injecting a 1Hz signal from the software.
Please see the attached diagram.
Looking forward to any comments or suggestions.
Kind Regards
Edward
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