BUS i2C Clock and PCF8575 [SOLVED]

[Jose Zazo]

I have redesigned my PCB to make it compatible with the new source code.

It compiles without problems but the clock does not work (the entire line is displayed with strange characters and the date or time cannot be set).

I have tried the I2C test code but it does not detect any device on the bus.

Attached layout scheme (I don't know why but I can't directly insert the image)

[Fernando Garcia]

Hi!

Wich RTC module are you using?

Can you try scan I2C BUS only with PCF connected?

Best regards.

[Jose Zazo]

I use the DS3231, it is the same one that I used with the old code on pins 18 and 19 and it worked correctly.

As for the test sketch I2C does not detect any device

If I remove the clock the result is the same:

Scanning ...
No I2C devices found

Thanks

[Fernando Garcia]

Can you scan only with RTC connected?

[Jose Zazo]

I have disassembled the PCB and directly connected the clock to pins 20 and 21 and it stays and GND and 5V from to Arduino

I2C Scanner
Scanning ...

If I do it with PCF8575 the same thing happens

[Fernando Garcia]

If connected directly to an Arduino it doesn't works so the problem should be with your Arduino.

You can try with another I2C module to make sure that this modules are not damaged.

Also can try with another Arduino Mega.