[TDA4VM] Treatment for SERDES_REFCLK

user5977526

Hello,

I have some questions for the SERDESx_REFCLKP/N.

1. It is marked as "IO" for the pin type in the DM. Could you inform me the detailed apllication for "input" and "output"? For example, in application of PCIe, which type of REFCLKP/N would be taken?

2. Do other SERDES applications also need this REFCLK like SGMII, USB3.0 and DP?

Many thanks in advance!

Fei Chen

over 5 years ago

0 Stanislav Stilyanov over 5 years ago

TI__Genius 15120 points

Hi Fei Chen,

1. You can use it either way. If it is output, TDA4 will supply the 100-MHz clock to the external PCIe device. In the EVM, and mostly used, is the external clock source IC (CDCI6214RGET). TDA4 and the external PCIe device are clock consumers. You can examine this case by looking at TDA4 EVM schematic - J7ES COMMON PROCESSOR BOARD.

2. Typically no

Regards,

Stan

0 user5977526 over 5 years ago in reply to Stanislav Stilyanov

Prodigy 50 points

Hi Stan,

Thanks for your support.

I have a further question. Is input/output related to PCIe role? When PCIe port is set as RC, REFCLK would be output. When PCIe port is set as EP, REFCLK would be input.

Best Regards,

Fei Chen

0 Stanislav Stilyanov over 5 years ago in reply to user5977526

TI__Genius 15120 points

Hi,

When RC, REFCLK can be input or output, depending on if internal clock (from SoC) or external clock chip (on PCB) is used.

When EP (add-on card), REFCLK is typically input.

Regards,

Stan

Processors

Processors forum

[TDA4VM] Treatment for SERDES_REFCLK