On 28 Jul 2010, at 02:52, DanielK wrote:
I have noticed that some designers use an Atmel microprocessor with an external RTC and TXO, others use an Atmel microprocessor with an integral crystal (surface mount), and still others like Moses use a Microprocessor without an external RTC but with an external TXO.
What are the advantages or disadvantages of these different appoaches. I am not sure how Moses gets the clock function from his microprocessor without a RTC.
I usually use a DS3231 in my new designs as it is compensated for ageing and temperature, does leap years, has 2 alarms etc. And it's easy to hang a supercap off it for battery backup.
For internal microprocessor generated timing I have successfully used PICs and Bresenham's algorithm. There is lots of information here:
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(scroll down - on my screen there is a big gap between the first picture and the rest of the page which you may miss)
John S
