IO/SPI.md

 Our SPI interface allows for interaction with IO devices that support SPI, for example SD cards.
 
-## Protocol 
+During SPI interaction we disable interrupts as to reduce the risk of the SD card timing out during data transfer.
 
-WIP
+## Commands 
+
+Our implementation realizes a subset of all possible SPI commands, namely the commands required for setting up SPI communication (namely `CMD0`, `CMD1` `CMD8`) and commands needed to read from and write onto an SD card (`CMD17` and `CMD24` respectively). 
+
+| Command | Name |
+| ------ | ------ |
+| CMD0 | GO_IDLE_STATE |
+| CMD1 | SEND_OP_COND |
+| CMD8 | SEND_IF_COND |
+| CMD17 | READ_SINGLE_BLOCK |
+| CMD24 | WRITE_BLOCK |
 
 ## Schematics