Re: Logic analyzer on ESP32 for self-diagnostics
Posted: Fri Jul 11, 2025 6:35 am
Thanks for the advice.Not sure if you're interested, but if you squirrel around in the SDK a bit, you can potentially make the P4 go much faster, probably up to 200MHz or so. Very high-level view: At least the PARLIO peripheral can also accept an external clock signal; I think this is specced for up to 80MHz but it can actually go a lot faster. (Possibly the LCDCAM module can do this as well, I haven't checked.) Additionally, if you make the PSRAM use the system PLL rather than the MPLL, you free that up for use as a random clock generator. You can then abuse the 50MHz output pin intended for Ethernet PHYs to output the clock signal; connect the PARLIO/LCDCAMs clock input pin to the same pin and it'll run on that clock signal. (But do note that on some silicon revs of the P4, the MPLLs clock frequency isn't quite stable: you may want to look into using other PLLs for that.)Added support for ESP32P4
I will definitely make a version for parlio
But I looked at the clock sources for PARLIO and CAM
For LCD/CAM, clocking is only from XCLK, PLL160 and APL
For PARLIO, an external clock is added. As far as I understand hardware (and I don't understand it very well), for stable data reception, you need to have at least *2 reference frequency, so jumping out of the standard 160/2 MHz will not work without changing the reference frequencies.
Since this project is intentionally done in such a way as to have minimal impact on running applications, changing the base frequencies is wrong