Raspberry Pi Pinout
GPIO I2C pHAT
The GPIO I2C pHAT is an I2C switch which mounts under your HAT to remap its I2C pins (GPIO 2 & GPIO 3) to 1 of 4 additional I2C buses, without the need for a multiplexer or expander.
Makes use of the extra hardware I2C buses introduced on Raspberry Pi 4 (BCM2711) or software I2C (bit bang). Switching is controlled using a 4-position double-pole slide switch, which allows you to quickly switch between buses.
Features
- Adds 4 additional I2C buses with breakout
- User selectable I2C GPIO pin remapping
- Hardware I2C compatible (Pi 4)
- Slide switch allows fast bus switching
- No-conflict solder jumpers
- Stackable design
- Immersion gold plated copper
Usage
Add required dtoverlay parameter(s) to /boot/config.txt and reboot.
Mount the GPIO I2C pHAT board to your Pi, use the slide switch to select your preferred I2C bus and stack your I2C based HAT on top.
Hardware I2C (Pi 4 Only)
dtoverlay=i2c3
dtoverlay=i2c4
dtoverlay=i2c5
dtoverlay=i2c6
Software I2C (Bit Bang)
dtoverlay=i2c-gpio,bus=6,i2c_gpio_sda=22,i2c_gpio_scl=23
dtoverlay=i2c-gpio,bus=5,i2c_gpio_sda=12,i2c_gpio_scl=13
dtoverlay=i2c-gpio,bus=4,i2c_gpio_sda=8,i2c_gpio_scl=9
dtoverlay=i2c-gpio,bus=3,i2c_gpio_sda=4,i2c_gpio_scl=5
Note: When using multiple software I2C buses, it's best to add the parameters from highest to lowest, i.e., 6, 5, 4, 3.
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