I have been asked to implement the 1G/10Gbe PHY design on Arria 10 based hardware that only provides a 644.53125 MHz reference oscillator. Our typical implementations include the 125 MHz reference for 1Gbe.
I have been able to build the design with two cascaded fPLLs producing the 125 and 625MHz references required for the 1GbE operational mode.
10GbE works just fine. 1Gbe mode does not work. When I try to switch to 1GbE the calibration sequence never completes; signal 'rc_busy' remains active..
I am monitoring signals from the reset controller. On a 1G reconfig that always fail the status ends up: rc_busy = ‘1’ , rx_is_lockedtodata_out = ‘0’, pll_locked = ‘1’, tx_analogreset = ‘0’, rx_analogreset= ‘0’, tx_digitalreset=’0’, rx_digitalreset=’1’, tx_cal_busy=’0’, rx_cal_busy=’0’
I'm looking for debug suggestions and/or implementation ideas (that don't use a 125MHz oscillator).
Pls see my comment below
I've attached an illustration of my clocking. The notable difference is the lack of a 125MHz reference clock and my using the 644.53125 with cascaded fPLLs to generate 1GbE references.
I will look at the reference design and see if there are any other differences I should be concerned about.