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FC10 Hardware I2C on MCP23017 not working
Posted: Thu Oct 19, 2023 9:49 pm
by pschoon
Hi,
Developed a small PIC16F18877 control board with MC23017 IO expander on it.
I2C to expander is working in software mode but not in hardware mode (channel 1)!
Re: FC10 Hardware I2C on MCP23017 not working
Posted: Fri Oct 20, 2023 10:14 am
by medelec35
Hello.
Thank you for the bug report.
I will be looking into this as soon as I can.
Re: FC10 Hardware I2C on MCP23017 not working
Posted: Sun Oct 22, 2023 7:43 pm
by medelec35
Hello.
The issue is caused by forcing the I2C pins low your expander is connected to.
It is a bad idea to force I2C high or low.
What you need to do is select Advance options of both outputs to port C and select:
Output to: Single Bit: 0
As this is not an I2C bug I have moved the topic to a more suitable location.