the frequency we test with oscilloscope is 99.77Mhz,
the clock frequency offset don’t meet the PCIE protocol standards
please help to dubug this problem.
Could you describe how and where you have measured this with waveform including statistics in the scope capture would help. Could you check if SSC is enabled or disabled? Also, measure with SSC disabled.
How to check the SCC is enabled or disabled ?
Please check the Orin NX tuning guide. The patch is provided inside of the PDF attachment.
Yes correct.
Which PCIe controller is that one got measured?
PCIEA X4 : PCIE0_0,1,2,3
PCIE clock A : PCIE0_CLK (PIN160/PIN162)
PCIEB X2 : CSI4_0,1,2,3
PCIE clock B: CSI4_CLK (PIN52/PIN54)
Is this measurement happened on PCIEA or PCIEB?
PCIEA
Hi
PCIeA on your board is PCIe C4 and C4 SSC could not be disabled.
So the frenquency is not changed we disable the SSC or not
And How to do next to solve this problem
So the frenquency is not changed we disable the SSC or not
You only disabled the SSC on your PCIEB. Not PCIEA. SSC on PCIEA cannot be disabled.
Seems some issue with your measurement. The clock amplitude seems too low if Vpp:48mV and Vmin: -27mV, Vmax:22mV. Do you have a scope to measure/check waveform? Please refer to PCIe specification for correct voltage levels.
How we do next to solve this problem ?
We meet the PCIe base specifications. What is the problem you are trying to solve here? Do you have any errors/failures? The measured frequency should be 99.97 to 100.03MHz without SSC. Please check if any issues at your end like equipment calibration, measure with proper time base to just show one clock cycle with infinite persistence enabled, trigger level, clock terminations, noise etc…
