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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
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
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
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