DP83822I: What is meant by turnarond time and Z in the diagram

Hello Prakash Prasad

Please see below 

Turnaround is defined as an idle bit time inserted between the Register Address field and the Data field. To avoid contention during a read transaction, no device may actively drive the MDIO signal during the first bit of Turnaround. The addressed DP83822 drives the MDIO with a zero for the second bit of turnaround and follows this with the required data.

Please refer to the below section to read about extended registers

8.4.2.1 Extended Register Space Access

Please read he below section and preceding sections 

8.4.2.2 Write Address Operation

Read Address Operation

Read (No Post Increment) Operation

Read (Post Increment) Operation

Can you provide more details on the context for these questions.

Regards,

Sreenivasa

Thanks - can you please explain a little more on the details - Is turnaround a value is of 2 bits to make the processor sleep for time specified or is just a dummy? So what does value 'Z0' means?

Also the context of differetn types of read operation (read / No Post Increment / Post Increment) is to understand what is the difference in between them or rather when to use each such operation?

Hello Prakash Prasad

Thanks you for the message.

It would help me answer your  questions if you could comment on the below,

Are you working on an active project or are you trying to understand  ? Do you have an EVM to try the configurations?

Regards,

Sreenivasa

Thanks for your reply too - actually I am currently understanding the documentation for a project which is in pipeline - repalcing Microchip PHY processor to TI DP83822I  in our control card. Hence curently all is at understanding level based upon which actual implementation would be done. We also do not have any EVM.

Hello Prasad, 

Thank you for the inputs.

If you read through the documentation, you will read about basic and extended register.

The Basic registers are accesses directly. IN extended register access has a defined format. 

No Post Increment / Post Increment provides way to access the registers in an optimized way.

Please read through DP83822 documentation and also some of the other PHY documentation like the DP83826, DP9399 to understand the register access.

Regards,

Sreenivasa

Hello Prasad, 

Quick note.

The need for extended register access is the PHY has a number of registers. Some are basic registers and other register are extended register.

Regards,

Sreenivasa