Forum Discussion

gbessa's avatar
gbessa
Icon for New Contributor rankNew Contributor
3 years ago
Solved

I2C Problem - Cyclone 10 GX dev kit

I'm using Cyclone 10 GX Development Kit and I'm trying to access (read/write) to the I2C I/O expander that interfaces with the SFP peripheral signals. This is very important to me because I need to...
  • gbessa's avatar
    gbessa
    3 years ago

    Hi,

    The problem is solved.

    The I2C slave device does not allow a read like I was doing. First there should be a write before the read. It has a specific pattern for each operation, concerning if it's a read or write and concerning the register that is accessed.
    These details are explained in the datasheet of the I2C external device (TI TCA9534PWR): https://www.ti.com/lit/gpn/tca9534

lixy's avatar
lixy
Icon for Contributor rankContributor
3 years ago

Hi gbssa,


I wonder if you are able to test the waveform with Oscilloscope.

The SignalTap waveform shows the internal signal. It would be helpful if we can know the exact signal on board both at the FPGA and the I2C slave side. There could be a situation that the signal is not correctly received by the slave, such as board-level transfer issue, I/O Pin issue, and so on.


Thanks & Regards,

Xiaoyan