Running MCP23017 via I2C on ESP-01

@Timothy3001

ok - you are running Espruino 1v86 on ESP01 and have D0 and D2

try this

var ESP8266 = require("ESP8266")
ESP8266.logDebug(false);

I2C1.setup({scl:D2, sda:D0}) ;
pinMode(D2,"opendrain");
pinMode(D0,"opendrain");

mcp = require("MCP23017").connect(I2C1, null, 0x20);

// and your code

check i2cdetect to find a i2c device on the bus