@spacelggo I do not remember what was the cause of slowness you can try to find info on the forum. I suppose that this was releated directly with SD driver not SPI itself. Someone tested this i do not tested this myself. I use always direct connection and built in driver.

@leo_sol Looking at your initial post it seems that UART1 may still available on both units. the default config collides with the SD card pins, but you can assign UART1 to other pins.

Thanks @daniel and @robert-hh and thank you for the offer of support and potential of modifying code base. I decided to use a PCA8575 16 bit I2C I/O expander as it solved the I/O problem without adding too much to the bill of materials, so I left the SPI pins for the Lora/Sigfox radio not connected.

Hello @seb and @livius , Thank you very much for your assistance with this, and it is awesome news about SPI.LSB. Cheers Colombian1976

@charly86 and while there at it they can also mention that p8 must not be pulled up when you want to flash the firmware. because if you don't it wont get into download_boot mode but instead into HSPI_FLASH_BOOT mode and will start a reset loop. we also had that problem.

@sjp770 SPI is a bus system. In a star configuration you can connect several slave devices to one master, as long as the (capacitive) load is not exceeded. But you need a CS for each device. If D/C is needed, you may be able to share it. If devices have active feedback pins like an Alarm pin, that has to be connected too to a separate I/O.

@jmarcelino D'oh! You'r right. It's a ESP32. After 20 years with Atmels and PICs, my mind falls back into this world... Cheers, Thomas

@soren Those pins are connected to the LoRa chip (SX1272) using SPI so you may see unexpected behaviour

I can offer the following info; The SPI is implemented in hardware. (I2C not yet, still software) Maximum clock rate is half the system clock frequency which currently is set at 160Mhz, so SPI clk can be as high as 80Mhz. Next slower frequency will be 40Mhz, then 20Mhz, then 10Mhz ......

@paulm Ignore recent post; I fixed this myself: https://forum.pycom.io/topic/4000/fixed-broken-sdcard-py-library-previously-impossible-to-have-external-spi-usd-card-with-pycom-boards

@RobTuDelft said in List of supported pins for various interfaces: TSL2591 The Adafruit board (or a clone)? https://www.adafruit.com/product/1980 If so then yes Adafruit added pull-up resistors which you don't really need on the Pycom boards.

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