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FPC402: random downstream reading (GBIC transceivers) return all zero. Only port reset resolve the issue

Part Number: FPC402

This issue randomly happen after several system reset then the  downstream reading (GBIC transceivers) return all zero. 

I check the I2C bus and there is no other device holding the bus as both SCL and SDA are high when the issue happen.

The issue only resolve if I reset the port accordingly (register 0x00 bit 0-3).  

My question:  what probably causing the FPC402 go into stuck mode and only port reset can help.



  • Hi Minh,

    Please note FPC402 programming guide. It is possible watch dog timer gets expired and this causes the FPC402 to terminate the I2C transaction. You may need to increase this timer length. You can also send us scope shot in normal and abnormal cases.