Bernie asked 2 days ago
Hi. I have run out of digital output ports. It appears that GPIO 34, 35, 36, 39, 2, 7, 8, 9, 10, 12, Rx0, Tx0, cannot not be used as output GPIOs. However, I am using GPIO 0, 4, 13, 14, 15.
The multiplexer 74HC4067 is recommended to set up extra addressable ports for an ESP32. But does this multiplexer retain the output value of the signal when it is deselected and another port is addressed? I do not think it does, as this device is an analog device. It probably sinks to LOW (or HIGH) when deselected? As I am directly driving relays, this is necessary.
Does the TCA9548A I2C multiplexer retain values upon deselection?
What is the best way to get hold of more output ports for the ESP32 or the ESP32-S3?
Thanks
Sara Santos Staff answered 2 days ago
Hi.
The best way to have more GPIOs is to use a multiplexer.
The one you mentioned is to use multiple I2C devices: https://randomnerdtutorials.com/tca9548a-i2c-multiplexer-esp32-esp8266-arduino/
For GPIO multiplexing, it’s recommended the MCP23017, for example.
At the moment, we don’t have any tutorials about that module.
Regards,
Sara