OK, so, problem eventually solved: 1. In the circuit diagram, I've got SD2(ESP32) -> SD2(PSRAM), and SD3(ESP32) -> SD3(PSRAM), because I incorrectly aligned SIO2(PSRAM) and SIO3(PSRAM) with SD2 and SD3 on the ESP32. 2. However, at one stage I did swap these two connections around (so the PSRAM shoul...

Thanks for the clarification abt SCK. I've connected the PSRAM64H to the ESP32 using a small PCB I made (pic attached), and DuPont wires. Perhaps the wires may be affecting the signal integrities. What would be the correct command to adjust the SPI0/1 clock frequency? Also, I'm taking it that you ag...

Yes, there seems to be activity (oscilloscope) on the pins, and I have used a multimeter to check the connections between the pads on the ESP32 WROOM module that correspond to the pins on the dev board, and they are all continuous and connected to the correct pads/pins. I'm wondering if just assumin...

Its a 38 pin ESP32 WROOM board.
The pinouts (shown below) expose GPIO6-11, which are the SPI pins for SPI1, and which I've connected the PSRAM64H chip to. Any further thoughts/advice appreciated.

I have connected an ESP PSRAM64H chip to an ESP32 WROOM board (38 pin, with SPI1 pins exposed (GPIO6, 7, 8, 9, 10)) following the same pin connections as for ESP32 WROVER B, as shown in the schematic below: PSRAM64HCOnnectedToESP32WROOM.jpg I have setup the board parameters to ensure PSRAM is select...