For some reason NVIDIA engineers decided to set output currents to some negligible 20uA and as a result made SPI and GPIO peripherals almost useless, very few microcontrollers can work with such low current. At least PIC32MZ cannot. Evidently I am not the first who deals with this issue. What is the best way to make it capable to communicate with a regular MCU via SPI port? I am considering two options: either add an adapter with a buffer chip between Jetson and MCU or find a better carrier board able to drive at least some mA. Thanks!
Yes, these pins output drivers are very weak due to connect to TI TXB0108 level translators. There is Jetson Nano Developer Kit 40-Pin Expansion Header GPIO Usage Considerations Applications Note for more info about this.
If the SPI device request stronger driver, a buffer or a custom carrier should be considered. You can check with vendors in ecosystem for that. Or, if you have good h/w ability, you can bypassing the level shift by removing the chip and connecting the SPI lines directly.