Occasional ContributorArria 10 Native Transceiver PHY 10GBASE-R w/KR FEC Clocks
Hello,
I am currently struggling with the Arria 10 Native Transceiver configured with the 10GBASE-R /wKR FEC preset.
I am using the following document as reference: https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/hb/arria-10/ug_arria10_xcvr_phy.pdf
In Figure 57 you can see that the tx_clkout and rx_clkout have 161.1 MHz and that the tx_coreclkin and rx_coreclkin are meant to have 156.25 MHz (from XGMII).
Now with the above mentioned preset the tx_pma_div_clkout is configured as 5156.25/33 = 156.25 MHz. The rx_pma_div_clkout is disabled.
My questions are:
1) Is the tx_pma_div_clkout destined to be used for my custom FPGA fabric (MAC, data preprocessing, ...) and the tx_coreclkin?
2) Shall I activate the rx_pma_div_clkout to do the same here? If so, why is it not activated by default?
3) If the answers to 1) and 2) are yes, what is the purpose of the tx_clkout and rx_clkout?
A similar question has already been asked here but unfortunately it wasn't answered.
https://community.intel.com/t5/Programmable-Devices/Arria-10-Native-Transceiver-PHY-10GBASE-R/m-p/16523
Thank you in advance!
Best Regards
Hi,
As I understand it, you have some inquiries related to the A10 Native PHY in 10GBaseR mode. Please see my responses as following:
1) Is the tx_pma_div_clkout destined to be used for my custom FPGA
fabric (MAC, data preprocessing, ...) and the tx_coreclkin?
[CP] Yes, your understanding is correct. This clock is of 156.25MHz which is to use with the XGMII interface and connect to xgmii_tx_clk/xgmii_rx_clk
2) Shall I activate the rx_pma_div_clkout to do the same here? If so,
why is it not activated by default?
[CP] You can use tx_pma_div_clkout for xgmii_tx/rx_clk. So, this clock is not used by default.
3) If the answers to 1) and 2) are yes, what is the purpose of the
tx_clkout and rx_clkout?
[CP] These are clocks used to clock in the internal blocks of the XCVR channels.
Please let me know if there is any concern. Thank you.
Best regards,
Chee Pin
