Portsdown 4 GPIO Connections
RPi 4 GPIO pin out
- Note the RPi4 (only) can be powered with 5v directly on to GPIO 2 and 4.
GPIO Connections for the Portsdown 4
Here is the initial list of GPIO connections.
| Pin No | BCM No | Wiring Pi | RPi Pri | RPi Alt0 | Primary Use | Secondary Use | Notes J0x Terminal blocks on GPIO breakout board. |
|---|---|---|---|---|---|---|---|
| 1 | - | - | 3.3v | - | - | - | - |
| 2 | - | - | 5v | - | - | - | - |
| 3 | 2 | 8 | GPIO 2 | SDA1 | - | - | - |
| 4 | - | - | 5v | - | - | - | - |
| 5 | 3 | 9 | GPIO 3 | SCL1 | - | - | - |
| 6 | - | - | 0v | - | - | - | - |
| 7 | 4 | 7 | GPIO 4 | GPCLK0 | Band D2 | Langstone band D5 | T for Transverter on J07. 10K resistor to GND |
| 8 | 14 | 15 | GPIO 14 | TXD0 | ADF5355 LE | Elcom LE | For future Sig Gen |
| 9 | - | - | 0v | - | - | - | - |
| 10 | 15 | 16 | GPIO 15 | RXD0 | Atten LE | - | 10 on J07 |
| 11 | 17 | 0 | GPIO 17 | FL1 | - | Langstone PTT | Active low |
| 12 | 18 | 1 | GPIO 18 | SPI6_CE0_N | Transmit Demand | Langstone CW Key | 12 on J07 |
| 13 | 27 | 2 | GPIO 27 | SD0_DAT3 | "Active" LED | - | Active high J06 S/D LED |
| 14 | - | - | 0v | - | - | - | - |
| 15 | 22 | 3 | GPIO 22 | SD0_CLK | Shutdown Button | - | Active high J06 |
| 16 | 23 | 4 | GPIO 23 | SD0_CMD | - | Langstone band D3 | - |
| 17 | - | - | 3.3v | - | - | - | - |
| 18 | 24 | 5 | GPIO 24 | SD0_DAT0 | - | Langstone band D2 | - |
| 19 | 10 | 12 | GPIO 10 | SPI0_MOSI | - | Langstone band D1 | - |
| 20 | - | - | 0v | - | - | - | - |
| 21 | 9 | 13 | GPIO 9 | SPI0_MISO | - | Langstone band D0 | - |
| 22 | 25 | 6 | GPIO 25 | SD0_DAT1 | - | Langstone band D4 | - |
| 23 | 11 | 14 | GPIO 11 | SPI0_SCLK | - | - | - |
| 24 | 8 | 10 | GPIO 8 | SPI0_CE0_N | - | - | - |
| 25 | - | - | 0v | - | - | - | - |
| 26 | 7 | 11 | GPIO 7 | SPI0_CE1_N | - | - | - |
| 27 | 0 | 30 | ID_SD | SDA0 | (was ADF4351 LE) | - | DO NOT CONNECT |
| 28 | 1 | 31 | ID_SC | SCL0 | (was Band D0) | (was Langstone band D7) | DO NOT CONNECT |
| 29 | 5 | 21 | GPIO 5 | GPCLK0 | spi clock | - | CLK on J04. 1K resistor. |
| 30 | - | - | 0v | - | - | - | - |
| 31 | 6 | 22 | GPIO 6 | GPCLK2 | spi data | - | DAT on J04. 1K resistor. |
| 32 | 12 | 26 | GPIO 12 | PWM0 | new Band D0 | new Langstone band D7 | Band select LSB now to I on J03 |
| 33 | 13 | 23 | GPIO 13 | PWM1 | new ADF4351 LE | - | Q on J03. 1K resistor. |
| 34 | - | - | 0v | - | - | - | - |
| 35 | 19 | 24 | GPIO 19 | SPI6_MESO | Band D1 | Langstone band D6 | Band Select MSB on J05 |
| 36 | 16 | 27 | GPIO 16 | FL0 | - | - | SR select LSB D0 on J02 |
| 37 | 26 | 25 | GPIO 26 | SD0_DAT2 | - | - | SR select NSB D1 on J02 |
| 38 | 20 | 28 | GPIO 20 | SPI6_MOSI | - | - | SR select MSB D2 on J02 |
| 39 | - | - | 0v | - | - | - | - |
| 40 | 21 | 29 | GPIO 21 | SPI6_SCLK | TX LED/PTT Drive out | - | TX LED J05 |
Note that the GPIO pin names are markedly different from the RPi 3B. Each pin on the RPi4 GPIO can be referred to in many ways: its physical pin number, the Broadcom I/O number, the Wiring Pi number or the primary or alternate names. Source for GPIO designations was the Raspberry Pi 4 Model B datasheet.
Note that no connections should be made to GPIO Pins 27 and 28, otherwise the RPi might get stuck on the Rainbow Screen at boot. Previous connections to these pins are being moved to other pins 32 and 33.
J0x terminal block identities relate to the BATC GPIO breakout PCB from the club shop..
Unused Willow breakout boards may work with Portsdown 4 because they needed extra connections to pins 27 & 28 on Portsdown 2018. These aren't required on P4 as noted here.
Pins 36, 37 & 38 may still be connected - G8GKQ has not knowingly disabled them - for extra DO, D1 & D2 connections - worth a try.