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fossasia / pslab-hardware

PSLab Hardware Design and Schematics https://pslab.io
Apache License 2.0
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Add another I2C bus #142

Closed bessman closed 9 months ago

bessman commented 1 year ago

Since the SDA1/RPI52/RC4 pin is now unused, we could add another I2C bus.

I believe that's all we need to do. Having another I2C bus would be very nice.

bessman commented 1 year ago

For the record, @RafaelLeeImg's comment on using this pin (not specifically for I2C):

The best way is to leave it open. I'm strongly against to make use of the last pin. I have spent a lot of time modifying the I2C bus to SPI due to the lack of free pins, Addition complexity is added, additional IC is required and software needs to be fixed too. If there are free pins before that moment, that kind of work could be easier. If an upgrade is needed, updating the chip to 64 pins will be suitable. The logic is not hard, but adding a chip means largely modify the layout of PCB which is also designed without any spare space, that means at least 20 hours of work.