0 : FREE (restrictions apply) 1 : UART0 TX 2 : FREE (restrictions apply) 3 : UART0 RX 4 : CAN RX 5 : CAN TX 6-11 : used by flash, not usable by apps 12 : FREE (restrictions apply) 13 : FREE 14 : FREE 15 : FREE 16 : OPS ENABLE 17 : OPS SIGNAL 18 : PROG ENABLE 19 : PROG SIGNAL 20 : DOESN'T EXIST 21 : I2C - SCL 22 : FREE (onboard led) 23 : I2C - SDA 24 : DOESN'T EXIST 25 : FREE 26 : FREE 27 : FREE 28-31 : DOESN'T EXIST 32 : FREE 33 : FREE 34 : FREE 35 : FREE SVP (36) : OPS CURRENT SENSE 37 : DOESN'T EXIST 38 : DOESN'T EXIST SVP (39) : PROG CURRENT SENSE