I am having a heck of a time getting I2C working with MCP23017 port expander. I've checked the connections, verified the values of my pullup resistors (4.7k) and so on but code that has worked before isn't working for me on these new boards.
While looking at the board, I noticed my 0805 100nF bypass caps seem unusually thick – they're about as thick as they are wide. I don't have a capacitance meter, but my "component tester" says they are around 130uF, not 100nF. It's possible that my assembler screwed these up.
It doesn't seem like this should matter much, but there are about 10 of them on the board. Do you think this would make a difference? Yes, reaching for straws at the moment....
The caps to the right of the crystal are 22pF, and I expect 100nF (C53 & C2) should be about the same thickness.
While looking at the board, I noticed my 0805 100nF bypass caps seem unusually thick – they're about as thick as they are wide. I don't have a capacitance meter, but my "component tester" says they are around 130uF, not 100nF. It's possible that my assembler screwed these up.
It doesn't seem like this should matter much, but there are about 10 of them on the board. Do you think this would make a difference? Yes, reaching for straws at the moment....
The caps to the right of the crystal are 22pF, and I expect 100nF (C53 & C2) should be about the same thickness.