One Minute/One Second Pulse generator. Ideal to be used to build any clock. Uses a 12F629. (05/31/2004)
CODE: JP6295 - PIC: 12F629
The hard part to build a clock is the one-second generator. I build 2 Digital clocks before and took many hours to calibrate it and get exactly one second. With this circuit, you can get one minute or one second without problems, you can use one of these xtals: 32.768Khz, 1 Mhz, 4 Mhz or 10Mhz. Here is the pinout information:
You can config the output as one-minute pulse or one-second pulse without dividers or additional components, just put the appropiate signal on MIN/SEC.
A good example how to use this circuit, here is a one-second generator using a 32.768Khz xtal:
The code was build based on Microchip data information (www.microchip.com) and Roman Black's web page.
NOTE: You have to read the xtal specifications, consult the data sheet from the manufacturer to know the capacitor value, type and hardware recommended. Without these specifications, may have a range of error up to 10 seconds every month.
Update: The reason why this projects is not longer available is because you can buy a $1 USD clock and use the circuit as timebase.
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