Referencing P 1484 RM0385, Table 247 (Rev 6 of this RM.)
The table shows bits for the operation field to be 10 or 01. I'm wprking with an Ethernet PHY that has extended function registers which are addressed by setting the Operation field to 00 and encoding the operation in the first bit of the PADDR field. Is it possible to generate this bit pattern using the ST IP?
Looking at the register ETH_MACMIIAR (p 1555, same RM) these bits are controlled by bit 1 "Bit 1 MW: MII write" so I think the IP will generate either '10' or '01' depending on this bit setting and it would be necessary to bit-bang this data stream to access the desired registers in the external device.
But I'll ask here in case I am wrong and there is a way to produce the desired bit stream using the ST IP.
Please prove me wrong!