Hier stelle ich mal eine Tablle rein mit allen Funktion der GPIO von Rpi B+ 1.2:
| PIN | Broadcom Name | ALT0 | ALT1 | ALT2 | ALT3 | ALT4 | ALT5 | STD | DEFAULT(BOOTUP) | BOOTUPVALUE |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | - | - | - | - | - | - | - | 3.3V | 3v3 | - |
| 2 | - | - | - | - | - | - | - | 5V | 5v | - |
| 3 | GPIO2 | SDA1 | SA3 | reserved | n/a | n/a | n/a | GPIO | IN | HIGH |
| 4 | - | - | - | - | - | - | - | 5V | 5v | - |
| 5 | GPIO3 | SCL1 | SA2 | reserved | n/a | n/a | n/a | GPIO | IN | HIGH |
| 6 | - | - | - | - | - | - | - | GND | GND | - |
| 7 | GPIO4 | GPCLK0 | SA1 | reserved | n/a | n/a | ARM_TDI | GPIO | IN | HIGH |
| 8 | GPIO14 | TXD0 | SD6 | reserved | n/a | n/a | TXD1 | GPIO | ALT0 (TXD0) | LOW |
| 9 | - | - | - | - | - | - | - | GND | GND | - |
| 10 | GPIO15 | RXD0 | SD7 | reserved | - | - | RXD1 | GPIO | ALT0(RXD0) | LOW |
| 11 | GPIO17 | reserved | SD9 | reserved | RTS0 | SPI1_CE1_N | RTS1 | GPIO | IN | LOW |
| 12 | GPIO18 | PCM_CLK | SD10 | reserved | BSCSL_SDA /MOSI | SPI1_CE0_N | PWM0 | GPIO | IN | LOW |
| 13 | GPIO27 | reserved | reserved | reserved | SD1_DAT3 | ARM_TMS | - | GPIO | IN | LOW |
| 14 | - | - | - | - | - | - | - | GND | GND | - |
| 15 | GPIO22 | reserved | SD14 | reserved | SD1_CLCK | ARM_TRST | - | GPIO | IN | LOW |
| 16 | GPIO23 | reserved | SD15 | reserved | SD1_CMD | ARM_RTCK | - | GPIO | IN | LOW |
| 17 | 3v3 | 3v3 | - | - | - | - | - | 3v3 | 3v3 | - |
| 18 | GPIO24 | reserved | SD16 | reserved | SD1_DAT0 | ARM_TDO | - | GPIO | IN | LOW |
| 19 | GPIO10 | SPI0_MOSI | SD2 | reserved | - | - | - | GPIO | IN | LOW |
| 20 | - | - | - | - | - | - | - | GND | GND | - |
| 21 | GPIO9 | SPI0_MISO | SD1 | reserved | - | - | - | GPIO | IN | LOW |
| 22 | GPIO25 | reserved | SD17 | reserved | SD1_DAT1 | ARM_TCK | - | GPIO | IN | LOW |
| 23 | GPIO11 | SPI0_SCLK | SD3 | reserved | - | - | - | GPIO | IN | LOW |
| 24 | GPIO8 | SPI0_CE0_N | SD0 | reserved | - | - | - | GPIO | IN | LOW |
| 25 | - | - | - | - | - | - | - | GND | GND | - |
| 26 | GPIO7 | SPI0_CE1_N | SWE_N/SPW_N | reserved | - | - | - | - | - | - |
| 27 | GPIO0/ID_SD | SDA0 | SA5 | reserved | - | - | - | GPIO (ID_SD ) I2C EEPROM | IN | HIGH |
| 28 | GPIO1/ID_SC | SCL0 | SA4 | reserved | - | - | - | GPIO (ID_SC) I2C EEPROM | IN | HIGH |
| 29 | GPIO5 | GPCLK1 | SA0 | reserved | - | - | ARM_TDO | GPIO | IN | LOW |
| 30 | - | - | - | - | - | - | - | GND | GND | - |
| 31 | GPIO6 | GPCLK2 | SOE_N/SE | reserved | - | - | ARM_RTCK | GPIO | IN | LOW |
| 32 | GPIO12 | PWM0 | SD4 | reserved | - | - | ARM_TMS | GPIO | IN | LOW |
| 33 | GPIO13 | PWM1 | SD5 | reserved | - | - | ARM_TCK | GPIO | IN | LOW |
| 34 | - | - | - | - | - | - | - | GND | GND | - |
| 35 | GPIO19 | PCM_FS | SD11 | reserved | BSCSL_SCL | SPI1_MISO | PWM1 | GPIO | IN | LOW |
| 36 | GPIO16 | reserved | SD8 | reserved | CTS0 | SPI1_CE2_N | CTS1 | GPIO | IN | LOW |
| 37 | GPIO26 | reserved | reserved | reserved | SD1_DAT2 | ARM_TDI | - | GPIO | IN | LOW |
| 38 | GPIO20 | PCM_DIN | SD12 | reserved | BSCSL_MISO | SPI1_MOSI | GPCLK0 | GPIO | IN | LOW |
| 39 | - | - | - | - | - | - | - | GND | GND | - |
| 40 | GPIO21 | PCM_DOUT | SD13 | reserved | BSCSL_CE_N | SPI1_CLK | GPCLK1 | GPIO | IN | LOW |
Auf Pin Nr 27 u 28 wird beim booten ein I2C -EEPROM gesucht, daher empfiehlt es sich, die Pins nicht zu belegen.
Quelle: Broadcom Datenblatt ARM Perepherials.BCM2835/ Raspberrypi.org Schematic Drawing of Rpi B+.