The boardcontroller and the Atmel ATmega1284P are connected together through TWI, SPI and USART. All interfaces can be used to communicate between the devices, but only the USART is implemented by default in the boardcontroller.
Table 8. Atmel ATmega1284P and boardcontroller communication interface
| Interface | Atmel ATmega1284P pin | Atmel AT32UC3B1256 pin |
|---|---|---|
| UART RX[a] | PD2 | PA24 |
| UART TX[a] | PD3 | PA23 |
| TWI SCL | PC0 | PA09 |
| TWI SDA | PC1 | PA10 |
| SPI SS[b] | PB4 | PA16 |
| SPI MOSI[b] | PB5 | PA14 |
| SPI MISO[b] | PB6 | PA25 |
| SPI SCK[b] | PB7 | PA17 |
[a] This represents the RX and TX on the Atmel ATmega1284P. The RX is connected to TX on the other device and visa versa [b] These signals can be disconnected from the boardcontroller by cutting the cut-straps marked SPI on the bottom side of the board | ||