Forum Discussion

danduan2's avatar
danduan2
Icon for New Contributor rankNew Contributor
5 years ago

intel FPGA clkusr pin

Hi, Intel, I want to know how to use clkusr pin for FPGA transceivers calibration and recalibration. Could you help to provide some advices? 1. if i want to use clkusr for my logic, 1) i a...
CheepinC_altera's avatar
CheepinC_altera
Icon for Regular Contributor rankRegular Contributor
5 years ago

Hi,


As I understand it, you have some inquiries related to the CLKUSR pin. For your information, if you are using XCVR in your design, at the board, you should connect the CLKUSR pin to dedicated free-running on-board oscillator with frequency of 100MHz - 125MHz. You would not need to do any instantiation in your design. Without connecting CLKUSR to free-running clock, the transceiver calibration could fail and lead to transceiver malfunction.


Also, it is recommended to use CLKUSR dedicated for transceiver calibration only.


Please let me know if there is any concern. Thank you.


danduan2's avatar
danduan2
Icon for New Contributor rankNew Contributor
5 years ago

Hi,

Thanks for your suggestion.

1. If i want to use usrclk pin for my own logic after transceiver power up calibration, is it ok?

2. what is the meaning of " If you are using the CLKUSR pin for your own logic (feeding it to the core), you must instantiate altera_a10_xcvr_clock_module altera_a10_xcvr_clock_module reset_clock (.clk_in(mgmt_clk));" (from cyclone10 transceiver userguide)