Raspberry Pi Display Parallel Interface (DPI) Jitter?

General Electronics
1

Hi everyone,

We’ve been experimenting with the DPI feature of the Raspberry Pi which offers a 24-bits parallel video output in addition to the HDMI output, and we’ve noticed some significant jitter on the pixel clock line as illustrated in the two attached images.

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Given that the feature is barely documented publicly by Broadcom, I felt like sharing, and I was curious to know if anyone else had any ideas on the matter.

Regards,

Nicolas

2

Hi Nicolas, probably not correlated at all but the Raspberry PI SPI clock will vary if the 5V supply is not stable. This is caused by the PWR_LOW_N signal from the PMIC to the SoC.
More info here: https://www.raspberrypi.org/forums/viewtopic.php?t=158777

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