DP83630: Status Frame, RMII and Half-Duplex

Alexey Tsirlin

Part Number: DP83630
Other Parts Discussed in Thread: DP83640,

Tool/software:

Hi,

I am trying to check DP83630 in half-duplex mode in PTP. It seems to me that the timestamps are not working. After reading the DP83640 Software Development Guide, section 3.1.8.5, I understand that there is a problem with using status frame with half-duplex RMII.

I just couldn't understand from the section if there is a problem, but it is possible to use status frames somehow or it is just impossible to use status frame and I must switch to interrupt and MDIO access to the timestamp.

Thanks!

Alexey.

7 months ago

0 Hillman Lin 7 months ago

TI__Mastermind 25955 points

Hi Alexey,

Thank you for following up. We will check it with the team and get back to you later.

--
Regards,

Hillman Lin

0 Vivaan Jaiswal 7 months ago

TI__Expert 6405 points

Hi Alexey,

Alexey Tsirlin said:
DP83640 Software Development Guide, section 3.1.8.5,

I was unable to find the document you are referring to on the product page. Could you please specify which document you are looking at?

Best,

Vivaan

0 Alexey Tsirlin 7 months ago in reply to Vivaan Jaiswal

Prodigy 75 points

National Semiconductor Ethernet PHYTER®
Software Development Guide

Rev 1.96

June 11, 2009

0 Vivaan Jaiswal 7 months ago in reply to Alexey Tsirlin

TI__Expert 6405 points

Hi Alexey,

Thank you for clarifying the document. Section 3.1.8.5 says that while using status frames in RMII mode, the CRS_DV signal may not be asserted properly, in accordance with the RMII specification. This can cause the device to perform un-deterministically since CRS_DV is a required signal for half-duplex RMII communication.

I believe this functionality should work in full-duplex mode since the CRS signal becomes redundant in this case.

Best,

Vivaan

0 Alexey Tsirlin 7 months ago in reply to Vivaan Jaiswal

Prodigy 75 points

Hi Vivaan,

My question is if it is somehow possible to use status frame in half-duplex RMII mode. From that document it seems that the answer is no.

Thanks,

Alexey.

+1 Vivaan Jaiswal 7 months ago in reply to Alexey Tsirlin

TI__Expert 6405 points

Hi Alexey,

Yes you are correct, it is not possible in half duplex mode. I believe our newer parts do support start of frame detect in half duplex mode if that is a requirement for this application.

Best,

Vivaan

Interface

Interface forum

DP83630: Status Frame, RMII and Half-Duplex