The spi is a high speed synchronous serial interface. avrforth currently initializes the spi to master mode running at maximum speed (clk/2). Slave select lines must be handled by the application code, although avrforth does initialize the ss line as an output to avoid automatically entering slave mode.
| word | stack | description |
|---|---|---|
| spi | ( -- ) | enable spi |
| /spi | ( -- ) | disable spi |
| spix | ( c1 -- c2 ) | transfer byte |
| spitx | ( c -- ) | send byte |
| spirx | ( -- c ) | receive byte |