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BenUhing's avatar
BenUhing
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4 years ago

Glitch on DCLK during Active Serial Arria 10

I have a PCB with an Arria 10 that I'd like to support both passive serial and active serial config. I can successfully configure the Arria 10 via JTAG and passive serial, but I cannot successfully p...
JohnT_Altera's avatar
JohnT_Altera
Icon for Regular Contributor rankRegular Contributor
4 years ago

Hi,


Not sure if this is due to your board trace? Have you check if there is any distortion that cause the issue?


BenUhing's avatar
BenUhing
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4 years ago

John,

It might be, but I have tried to eliminate the possibility. I have attached a screen grab of the layout. The purple vias are at the back of the Arria 10. R638 is the 22 ohm series termination resistor. I have tried removing R638 and installing a 1k ohm resistor from DCLK at the right pad of R638 to ground. I can still see the glitch with just 330 mils of trace.

What is the source of the output clock on DCLK when programming a flash and trying to boot from one using Active serial? Is it the internal oscillator or is it dependent on CLK_USER? I also have other differential clocks input to IOs, but I don't think the flash loader design has any way of knowing they're clocks before configuration.

If it matters, we're using the 10AX090N2F40E2SGJZ.