CANADUINO D1 Mini GPIO Expander I2C 8-Channel

CANADUINO® D1 Mini GPIO Expander I2C 8-Channel

The CANADUINO® D1 Mini GPIO Expander adds 8 extra digital input/output pins to your D1 Mini setup.

This module is based on the PCF8574 I2C expander chip and communicates via the D1 Mini’s standard I2C pins (D4 = SDA, D5 = SCL). Multiple compatible Arduino libraries are available.

The default I2C address is 0x23. A solder jumper on the back of the module allows changing the address to 0x21, enabling the use of two GPIO expander modules on the same I2C bus or helping avoid address conflicts with other devices.

Each GPIO pin includes a 10kΩ pull-up resistor to 3.3V. Therefore:

• Writing “HIGH” releases the pin with a weak pull-up (3.3V).
• Writing “LOW” actively drives the pin low, sinking up to 25mA per channel.

Headers and terminal blocks are included - not factory assembled.

Code Example (Download here):

GPIO pins 0 to 3 are initialized as outputs. A HIGH bit is cycling through them, making one step every 2 seconds.
GPIO pins 4 to 7 are initialized as inputs. Their value is sent to the serial monitor.
The demo is compiled for the D1 Mini ESP8266 and the D1 Mini OLED shield.(Download)