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Transceiver PLL powerdown




I am using Arria 10 development board.


In my design I am using Arria 10 transceiver in Native PHY mode.


I have integrated transceiver + reset controller + fpll as arria 10 transceiver user guide.


When bitstream is flashed I see transmit clock being generated by fpll.

When I press reset button and release it then fpll stops generating transmit clock. I believe that reset controller is not releasing powerdown signal to fpll.


I have a free running reference clock.


Any thoughts on why fpll is not generating transmit clock when reset button is pressed ?


Thanks & Regards,

Sachin Jadhav


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Hi Sachin, As I understand it, you have some inquiries related to the A10 fPLL for XCVR. Based on your description, seems like after programming the device, your design is working fine with fPLL transmitting clock. However, after you press a reset button, the fPLL seems not output any clock. Issue seems to occur after pressing of the reset button. To ensure we are on the same page, just would like to check with you on the following: 1. After programming the device, just would to check with you how do you monitor if the fPLL is transmitting clock? Is it base on the XCVR traffic is working fine? Or you are monitor the pll_locked output signal from fPLL? 2. Regarding the reset button, just would like to check with you if it is a user push button on the devkit which is connected to the reset controller input reset port? 3. When you refer to no clock from the fPLL, is it that the pll_locked = 0? 4. Just wonder if you have had a chance to SignalTap the pll_powerdown, pll_locked and pll_cal_busy signals so that we can have further understand on the fPLL when issue occurs. 5. It would be great also if you could signal all the signals of the reset controller to see if can spot any anomaly. 6. Mind double check if the CLKUSR and PLL refclk are connected to free-running oscillators on board just to isolate any power up calibration related issues. 7. What is the specific A10 devkit that you are currently using? Please let me know if there is any concern. Thank you. Best regards, Chee Pin
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