MCP23017

Introduction

The number of GPIO pins on the ESP module can be expanded with a IO Expander. We will use the MCP23017 that provides 16 more pins that can be used as input or output. This way it becomes possible to control a 16 channel relay board.

Each individual pin can be used as either input or output.

Hardware

The MCP23017 needs to be connected through the I2C interface. This chip is compatible with 3V3 and it can be connected to the ESP without levelshifters..

Connections

 MCP23017 	ESP-01
 GND 	 	GND
 VCC    	VCC
 SDA		GPIO 0
 SCL		GPIO 2

ESP Easy

Configuration depends on how you want to use a certain port on this device. Ports are numbered 1 to 16 (if you have a single MCP23017 connected)

Input

To have an input port act as an input switch device (just like with the default onboard GPIO pins) you need to edit a ESP Easy task and select the "MCP23017 input" device.

You then select the portnumber and additional configuration depending on the controller type. For Domoticz, you enter the IDX that was allocated by Domoticz for this virtual switch.

Portnumbering depends on the I2C address used:

A0:	A1:	A2:	Address:	Port range:
0	0	0	0x20	1 - 16
1	0	0	0x21	17 - 32
0	1	0	0x22	33 - 48
1	1	0	0x23	49 - 64
0	0	1	0x24	65 - 80
1	0	1	0x25	81 - 96
0	1	1	0x26	97 - 112
1	1	1	0x27	113 - 128

Commands

Command	Value	Extra information
MCPGPIO,<pin>,<value>	1,0	Control MCP23017 output pins (1 or 0)
MCPPulse,<pin>,<value>,<duration>	1,0	Pulse control on MCP23017 output pins (duration in mS, MILLIseconds)
MCPLongPulse,<pin>,<value>,<duration>	1,0	Pulse control on MCP23017 output pins (duration in S, seconds)