As the ESPuno Pi Zero also has a PCA9671 on default address 0x20, ensure you set the PGEZ I2C address away from the 0x20. Then update the below PCA_Address. See Wiki ...

Abstract: I2C abbreviation is Inter Integrated Circuit. It is a serial bus protocol found by Philips Semiconductor. I2C bus is popular because it is simple to use. I2C protocol is used for ...

This great IC allows the user to expand up to 16 I/O using only two I/O for control! The PCF8575C is controlled through an I2C interface and features 16-bits of quasi-bidirectional input/output pins.