Xplained Pro Standard Extension Headers

The ATMEGA256RFR2 Xplained Pro headers EXT1, EXT2, EXT3, EXT4, and EXT5 offers access to the I/O of the microcontroller in order to expand the board e.g. by connecting extension modules to the board. These headers all comply with the standard extension header specified in Table 1. All headers have a pitch of 2.54mm.

Table 1. Extension Header EXT1
Pin on EXT1 ATmega256RFR2 pin Function Shared functionality
1   Communication line to ID chip on extension board  
2   GND  
3 PF0 ADC0  
4 PF1 ADC1  
5 PE2 GPIO  
6 PE3 GPIO  
7 PB5 OC1A EXT4 header
8 PB6 OC1B  
9 PE5 GPIO / INT5 EXT4 header
10 PD5 GPIO / SPI chip select B EXT4 header
11 PD1 TWI SDA All EXT headers
12 PD0 TWI SCL All EXT headers
13 PE0 UART0 RXD All EXT headers. EXT2, EXT3 and EXT5 connected through cut-strap.
14 PE1 UART0 TXD All EXT headers. EXT2, EXT3 and EXT5 connected through cut-strap.
15 PG0 GPIO / SPI chip select A EXT4 header
16 PB2 SPI MOSI All EXT headers
17 PB3 SPI MISO All EXT headers
18 PB1 SPI SCK All EXT headers
19   GND  
20   VCC  
Table 2. Extension Header EXT2
Pin on EXT2 ATmega256RFR2 pin Function Shared functionality
1   Communication line to ID chip on extension board  
2   GND  
3      
4      
5      
6      
7      
8      
9 PE6 GPIO / INT6 EXT5 header
10 PD6 GPIO / SPI chip select B EXT5 header
11 PD1 TWI SDA All other EXT headers
12 PD0 TWI SCL All other EXT headers
13 PE0(1) UART0 RXD All other EXT headers. EXT2, EXT3 and EXT5 connected through cut-strap.
14 PE1(1) UART0 TXD All other EXT headers. EXT2, EXT3 and EXT5 connected through cut-strap.
15 PD4 GPIO / SPI chip select A EXT5 header
16 PB2 SPI MOSI All other EXT headers
17 PB3 SPI MISO All other EXT headers
18 PB1 SPI SCK All other EXT headers
19   GND  
20   VCC  
Note:
  1. Connected through cut-strap.
Table 3. Extension Header EXT3
Pin on EXT3 ATmega256RFR2 pin Function Shared functionality
1   Communication line to ID chip on extension board  
2   GND  
3 PF3 GPIO  
4 PG5 GPIO  
5 PB7 GPIO  
6      
7      
8      
9 PE7 GPIO / INT7  
10 PD7 GPIO / SPI chip select B  
11 PD1 TWI SDA All other EXT headers
12 PD0 TWI SCL All other EXT headers
13 PE0(1) UART0 RXD All other EXT headers. EXT2, EXT3 and EXT5 connected through cut-strap.
14 PE1(1) UART0 TXD All other EXT headers. EXT2, EXT3 and EXT5 connected through cut-strap.
15 PG2 GPIO / SPI chip select A  
16 PB2 SPI MOSI All other EXT headers
17 PB3 SPI MISO All other EXT headers
18 PB1 SPI SCK All other EXT headers
19   GND  
20   VCC  
Note:
  1. Connected through cut-strap.
Table 4. Extension Header EXT4
Pin on EXT4 ATmega256RFR2 pin Function Shared functionality
1   Communication line to ID chip on extension board  
2   GND  
3      
4      
5      
6      
7 PB5 OC1A EXT1 header
8      
9 PE5 GPIO / INT5 EXT1 header
10 PG0 GPIO / SPI chip select B EXT1 header
11 PD1 TWI SDA All other EXT headers
12 PD0 TWI SCL All other EXT headers
13 PE0 UART0 RXD All other EXT headers. EXT2, EXT3 and EXT5 connected through cut-strap.
14 PE1 UART0 TXD All other EXT headers. EXT2, EXT3 and EXT5 connected through cut-strap.
15 PD5 GPIO / SPI chip select A EXT1 header
16 PB2 SPI MOSI All other EXT headers
17 PB3 SPI MISO All other EXT headers
18 PB1 SPI SCK All other EXT headers
19   GND  
20   VCC  
Table 5. Extension Header EXT5
Pin on EXT5 ATmega256RFR2 pin Function Shared functionality
1   Communication line to ID chip on extension board  
2   GND  
3      
4      
5      
6      
7      
8      
9 PE6 GPIO / INT6 EXT2 header
10 PD4 GPIO / SPI chip select B EXT2 header
11 PD1 TWI SDA All other EXT headers
12 PD0 TWI SCL All other EXT headers
13 PE0(1) UART0 RXD All other EXT headers. EXT2, EXT3 and EXT5 connected through cut-strap.
14 PE1(1) UART0 TXD All other EXT headers. EXT2, EXT3 and EXT5 connected through cut-strap.
15 PD6 GPIO / SPI chip select A EXT2 header
16 PB2 SPI MOSI All other EXT headers
17 PB3 SPI MISO All other EXT headers
18 PB1 SPI SCK All other EXT headers
19   GND  
20   VCC  
Note:
  1. Connected through cut-strap.
Parent topic: Connectors