DS1307 doesn't keep day of the month

[temtronic]

OK, silly question but have you tried another DS1307 RTC chip ? While rare, maybe part of that one is damaged? I've used that RTC for years and never had a problem. There's a 'driver' for it in the CCS package or in the 'code library' here. The 4K7 pullups are should be fine for 5 volts but I use 3k3.

Also there might be a 'bug' in the driver you're using, perhaps a mislabeled variable or the correct one misused ?

Another way to attack it is to use a spare I/O pin as a serial output and send the data to a PC running a terminal program. You'll need a max232 type chip on the O/P to the PC but it should be easy enough to hack in for test purposes. I always dedicate one pin to be for 'test' LED / 'serial output'.

Without the real hardware and code it is difficult to troubleshoot 'over the internet.

Jay

[AnthonyRFC]

Hi all:

I could finally fix the problem using: