I/O expansion headers

There are 4 available IO expansion headers on the kit. Some pins have shared functionality with on board functionality. If “clean” expansion ports are needed, there are available cut-straps on some of the ADC inputs to remove onboard functionality. Table below show what is shared on the respective header pins.

Table 1. UC3-C2 Xplained I/O expansion header - J1
Pin J1 UC3 pin Shared with onboard functionality
1 TWI SDA PC02 Ethernet(MDC)
2 TWI SCL PC03 Ethernet(MDIO)
3 USART RXD PD12 Ethernet(TXD1)
4 USART TXD PD11 Ethernet(TXD0)
5 SPI CS PD30 Ethernet(TXEN)
6 SPI MOSI PD27 Ethernet(RXER)
7 SPI MISO PD28 Ethernet(RXDV)
8 SPI SCK 1 PD29 Ethernet(TXCLK)
9 GND    
10 VCC_P3V3    
Table 2. UC3-C2 Xplained I/O expansion header - J2
Pin J2 UC3 pin Shared with onboard functionality
1 ADC0 PA19  
2 ADC1 PA22 RC Filter output
3 ADC2 PA20  
4 ADC3 PA21  
5 ADC42 PA06 NTC
6 ADC5 PA07  
7 ADC62 PA08 Double LED (Red)
8 ADC72 PA09 Ethernet(Reset)
9 GND    
10 VCC_ANA_P3V3    
Table 3. UC3-C2 Xplained I/O expansion header - J3
Pin J3 UC3 pin Shared with onboard functionality
1 PWM0 PC15 LED0, Qtouch Key0
2 PWM1 PC16 Dataflash(CS)
3 CAN-RX PC21  
4 CAN-TX PC22  
5 GPIO PD13 Ethernet(RXD0)
6 GPIO PD14 Ethernet(RXD1)
7 GPIO 3 PD21 LED2, Mechanical Button
8 GPIO PA23 LED1, Qtouch Key1
9 GND    
10 VCC_P5V0    
Table 4. UC3-C2 Xplained I/O expansion header - J4
Pin J4 UC3 pin Shared with onboard functionality
1 TWI SDA PC04  
2 TWI SCL PC05  
3 USART RXD PC18  
4 USART TXD PC17  
5 SPI CS PD03  
6 SPI MOSI PD00 Dataflash
7 SPI MISO PD01 Dataflash
8 SPI SCK PD02 Dataflash
9 GND    
10 VCC_P3V3    
Note: The header support Atmel 10 pin WLESS module.
Parent topic: Connectors
1 The SPI SCK shared with Ethernet reference clock, can be connected from onboard function by mounted zero resistor on the top side of the board.
2 ADC channels can be disconnected from onboard functions by cutting the available cut-straps on the bottom side of the board.2
3 Mechanical button and LED0 is sharing IO. Use input with pull-up to turn off LED, and output low to turn on LED. 2. The VCC pin on this header has 5V and is connected to the USB power.