Problem with DS1307 and 40X1

[cherub66696]

Hi there.
I have a home made data logger with the circuit from the AXE110 (had to add other components) but after writing the i2c code and reading back all i get is 255 | #FF but the 1sec led does flash.

I have tried almost all the other codes on the forums but to no avail! i have the pull up resistors in place and the circuit seems clean...dunno what is going wrong.

Thank you
Chris

 

[BeanieBots]

Sounds like a break in one or other of the I2C lines or one or the other is being forced high for some reason.
First thing to try (besides double checking the circuit) would be to remove all other devices from the I2C bus.

Can you read/write OK to/from EEPROM on the same board?

 

[Technical]

Make sure the sda and scl are around the correct way. An old version of the AXE110 datasheet did have the connections incorrectly shown the wrong way around. The 18X pinout in the manual1 shows the correct SDA / SCL pins.