Raspberry Pi Display Parallel Interface (DPI) Jitter?

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.


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

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