This port is not exposed by default, and a modified back cover needs to be used to make it accessible. For this reason the port is also named the “internal expansion port”.
Pinout
| Function | Name | GPIO | Description | Notes |
|---|---|---|---|---|
| Power output | VOTG | - | Output from booster DC/DC converter in the PMIC | 5 volt when booster is enabled, +/- VSYS when booster is disabled |
| USB | HUB_USB1_P | - | Port on USB hub for USB-C port (DP) | Can be used to expose an USB device on the add-on to the PC plugged into the USB-C port |
| Power output | HUB_USB1_N | - | Port on USB hub for USB-C port (DN) | Can be used to expose an USB device on the add-on to the PC plugged into the USB-C port |
| USB | VBATT | - | Battery voltage (3.0 – 4.2v) | Directly connected to battery connector, always on even when the device is turned off |
| Power output | VSYS | - | System voltage (3.0 – 5.0v) | Switched power rail for powering the system, can be powered by battery or USB-C port, off when device is turned off |
| Power ref. | GND | - | Voltage reference (ground) | |
| Power ref. | GND | - | Voltage reference (ground) | |
| Power output | +3.3v | - | Main logic supply rail (3.3v) | |
| I2C | INT_SCL | Internal I2C bus, shared with other I2C devices (SCL) | Used to connect I2C devices and an EEPROM for add-on identification | |
| I2C | INT_SDA | Internal I2C bus, shared with other I2C devices (SDA) | Used to connect I2C devices and an EEPROM for add-on identification | |
| GPIO | E0 | 36 | GPIO | |
| GPIO | E1 | 0 | GPIO | |
| GPIO | E2 | 6 | GPIO, also connected to camera GPIO 1 | Shared with camera connector |
| GPIO | E3 | 46 | GPIO, VSDCARD LDO must be enabled to use this pin | Connected via level shifter, externally these GPIOs operate at 3.3v but the GPIOs are powered by the VSDCARD power domain |
| GPIO | E4 | 47 | GPIO, VSDCARD LDO must be enabled to use this pin | Connected via level shifter, externally these GPIOs operate at 3.3v but the GPIOs are powered by the VSDCARD power domain |
| GPIO | E5 | 48 | GPIO, VSDCARD LDO must be enabled to use this pin | Connected via level shifter, externally these GPIOs operate at 3.3v but the GPIOs are powered by the VSDCARD power domain |
| GPIO | E6 | 45 | GPIO, VSDCARD LDO must be enabled to use this pin | Connected via level shifter, externally these GPIOs operate at 3.3v but the GPIOs are powered by the VSDCARD power domain |
| GPIO | E7 | 7 | GPIO, in low power domain of P4, has 51k pull-up resistor | Can be used as wakeup pin to wake up the ESP32-P4 from deep sleep |
| GPIO | E8 | 54 | GPIO | |
| GPIO | E9 | 49 | GPIO | |
| GPIO | E10 | 53 | GPIO | |
| GPIO | EXT_USB_P | 26 | Can be used as GPIO or as USB FS PHY (DP) | The USB PHYs of the P4 can be swapped between the USB serial/jtag and user controlled USB peripheral. If badgelink is used then this PHY exposes the serial/jtag peripheral |
| GPIO | E11 | 52 | GPIO | |
| GPIO | EXT_USB_N | 27 | Can be used as GPIO or as USB FS PHY (DN) | The USB PHYs of the P4 can be swapped between the USB serial/jtag and user controlled USB peripheral. If badgelink is used then this PHY exposes the serial/jtag peripheral |
| GPIO | E12 | 51 | GPIO | |
| GPIO | P4_TX | 37 | Exposes boot console of P4, can be used as GPIO | Must be low during boot |
| GPIO | E13 | 50 | GPIO | |
| GPIO | P4_RX | 38 | Exposes boot console of P4, can be used as GPIO | Must be high during boot |
| I2S | I2S_MCLK | Digital audio bus master clock | Reference clock for connected I2S devices | |
| I2S | I2S_LRCK | Digital audio bus word clock | Word clock (left-right selection) for connected I2S devices | |
| I2S | I2S_DATA | Digital audio bus data output | Data output from mainboard for connected I2S DACs | |
| I2S | I2S_SCLK | Digital audio bus sample clock | Sample clock for connected I2S devices | |
| Power output | +3.3v | - | Main logic supply rail (3.3v) | |
| I3C | I3C_SDA | I3C bus, shared with QWIIC connector (SDA) | Can also be used as I2C bus | |
| Power ref. | GND | - | Voltage reference (ground) | |
| I3C | I3C_SCL | I3C bus, shared with QWIIC connector (SCL) | Can also be used as I2C bus |
Limitations & warnings
- Total for all 3.3v outputs must not exceed 1A of current. It is generally adviced to stay well below this figure.
- Do not exceed a current of 1.5A from the battery when the battery is connected to the internal battery connector
- Do not charge the battery via the internal add-on port