https://github.com/christinaa/rpi-open- ... #L436-L461It perhaps depends on how low the Pico can negotiate the bus speed down to.
this is an old SD driver for the open firmware
you can see here, where its detecting what version of the SD protocol the card implements, and then picks a clock divisor that sets the right clock rate
so if you just advertise yourself as version 1, a sane host would run at a slower clock rate
The device i am looking to try this with is normally trying to use the 'high speed' mode, it runs normally at 44mhz. i am not sure if saying you support only lower speed would actually work, but i could give it a go, and see
Statistics: Posted by LiEnby — Sat Apr 13, 2024 6:35 am