Unable to read PHY identification Number in TJA1100 ETH PHY

[channakeshava_s]

Hello All,

We are using #TJA1100 ETH PHY for BroadReach ETH communication, 

Connection is as follows:

Microcontroller is connected to TJA1100 via RMII.

PHY is controlled by uc using MDIO, MDC PINs.

The following configuration are made for PHY:

Config0: LOW (Configured as Slave)

Config1: LOW (Managed operation)

Config2: LOW

Config3: HIGH

So, RMII mode (25MHz)

and uc is configured with all required port pin settings.

Problem: Could not establish connection with PHY through RMII. so PHY ID also could not be read.

Whether MDC clock will affect communication with PHY?

Thank you.

Regards,

Channa

[bpe]

Neither MAC, nor PHY sends any acknowledgement of any unit
of data transfer over RMII in either direction, so it is not clear what
exactly was meant with "Could not establish connection with PHY through
RMII". PHY ID as well as other control information is exchanged over
SMI, for which MDC clock is mandatory. Suggestion: read any valid
management register address in a loop, inspect SMI signals
with a scope, make sure they have valid timing and shapes.

Hope this helps,

Platon