Is this on a breadboard? I have found SPI to be flaky on breadboards. You could try different clock frequencies. Adding grounds might help. For the signal lines, try adding ~33Ω series resistors as close as possible to the driving end and/or you can tweak the Pico ends with gpio_set_slew_rate, gpio_set_drive_strength, and gpio_set_input_hysteresis_enabled.
Statistics: Posted by carlk3 — Fri Jul 26, 2024 4:37 pm