Thank you for the reply, lbernstone. I confirmed and yes, the SPI clock does change when changing the SPISettings in the sketch. The factors of expected clock frequency and measured one is always the same (40 / 90, same as the two clocks).

I'll get in contact with the guys from the Arduino ...

After a bit of further digging, it seems like the "SPI clock divider" is correctly set up for a 90 MHz clock:

Serial.printf("Current divider: %d", SPI.getClockDivider());

gives a raw value of 2101249 = 0x201001. This would ( I believe) correspond to

CLKCNT_N = 1
CLKCNT_H = 0
CLKCNT_L = 1
CLKDIV ...

Hello,

I am using the Waveshare ESP32-P4-ETH module and programming it via the Arduino IDE. Uploading and debug output are working fine via the USB connection.

However, when setting up the SPI and performing a transfer at 5 MHz clock speed, the actual SPI clock signal is only clocking at 2.222 MHz ...

are there any updates on (planned) NuttX support on the P4? We, too, would be very much interested.