5 years, 3 months ago.

ds1307 rtc with redbearlab nano

Does anybody know how to use this ds1307, https://digitalmeans.co.uk/shop/realtime_clock_module_ds1307-v1-1?search=clock, with this BLE nano, http://redbearlab.com/blenano/.

Right now I am using this libary, https://developer.mbed.org/users/harrypowers/code/DS1307/.

The problem is that I am getting r/w problems shown in this image,


I have everything wired up correctly, but I just cannot figure out what is wrong with it. Any help is appreciated.

EDIT: I am sorry if I sound grumpy, but I really need sleep, :).

1 Answer

5 years, 3 months ago.

It looks like some of the I2C accesses are working. Do you know if it is always the same transactions that fail? I2C uses open drain outputs and the high state is not strong so the rising edges can be slow and the bus can be sensitive to noise and crosstalk. You might want to shorten the I2C wires and increase the strength of the pull-up (maybe add another 4.7k to the blenano)