Hello,
We are currently using TMDS181 in snoop mode on our boards.
Recently, we came across an issue on the DDC bus: We have discovered that some laptops make the distinction between HDMI / DCI based on what is read from the DDC (I2C link) at device address 0x80.
All TVs and Monitor we have tested so far respond with a 16 bytes sequence x"44", x"50", x"2D", x"48", x"44", x"4D", x"49", x"20", "41", x"44", x"41", x"50",x"54", x"4F", x"52", x"04". (‘DP-HDMI ADAPTOR’)
On our boards, there was no such response given: I2C request at slave address 0x80 received a NACK response.
So we added a small module that reply to slave address 0x80 with the correct bytes.
Unfortunately, as soon as we responding with ACK to slave address 0x80, another device on the I2C bus suddenly start responding as well!
The only other device having access to the DDC bus is the TMDS181; We suspect this response come from the TMDS181.
Is it possible for TMDS181 to drive SDA line when slave address is 0x80?
Kind regards,
