Hi team,
My customer is using TMDS361 HDMI 3 to 1 switch in their project. They want to use this device to implement below function:
when any of the 3 HDMI input ports plug in, the system detect the port #, and switch the receiver side to that port.
What they did now is using a MCU's GPIO to detect the voltage on I2C pins (SCLx, SDAx). they think when the HDMI inserted, these pins would go high (pulled up by the input source), then it would tell the MCU which port is inserted. However, they found something wrong: if the receiver side is already connected to an active HDMI port, there would be a bias voltage on the selected input port's SDA,SCL pin, although it is floating. then it makes it difficult for the MCU to do input plug in indication.
Thus, could you please help check below questions?
1. why is there a bias voltage on the SDA/SCL pin of the input side, which is from receiver side I2C termination voltage? For customer's test, the termination voltage on sink (receiver) side is 3.3V, and the bias voltage they measured is 2.5V. please help check the internal circuit to cause it.
2. any better suggestions for this input plug in indication?
Thanks.
BR,
Mike
