78 lines
2.0 KiB
Lua
78 lines
2.0 KiB
Lua
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--[[
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This example demonstrates how to use the different functions of the mcp23017 lua module.
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@author Marcel P. | Plomi.net
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@github https://github.com/plomi-net
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@version 1.0.0
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--[[
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initialize and setup
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]]
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-- initialize module
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local mcp23017 = require "mcp23017"
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local address = 0x20 -- the address for MCP23017 (between 0x20 and 0x27)
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local cSCL = 1 -- SCL pin = 1 = D1 / GPIO 5 (ESP8266)
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local cSDA = 2 -- SDA pin = 2 = D2 / GPIO4 (ESP8266)
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local i2cId = 0 -- i2c id
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-- setup i2c bus and create instance for mcp23017 (assigned to mcp)
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i2c.setup(i2cId, cSDA, cSCL, i2c.SLOW)
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local mcp = mcp23017(address, i2cId)
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--[[
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set output and input channels
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]]
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-- set pin 7 and 8 to output (GPA7 and GPB0) and GPB1 to input
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mcp:setMode(mcp.GPA, 7, mcp.OUTPUT)
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mcp:setMode(mcp.GPB, 0, mcp.OUTPUT)
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mcp:setMode(mcp.GPB, 1, mcp.INPUT)
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--[[
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set output channels to high and low
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]]
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-- set pin 7 to high (GPA7)
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mcp:setPin(mcp.GPA, 7, mcp.HIGH)
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-- set pin 8 to low (GPB0)
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mcp:setPin(mcp.GPB, 0, mcp.LOW)
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--[[
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toggle pin 6 channel state every second (blinking)
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]]
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local currentPin = 6
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local currentReg = mcp.GPA
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local currentState = false
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mcp:setMode(currentReg, currentPin, mcp.OUTPUT)
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tmr.create():alarm(1000, tmr.ALARM_AUTO, function()
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if currentState == true then
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-- print("set to low")
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mcp:setPin(currentReg, currentPin, mcp.LOW)
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currentState = false
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else
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-- print("set to high")
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mcp:setPin(currentReg, currentPin, mcp.HIGH)
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currentState = true
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end
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end)
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--[[
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read input channels and display every 7 seconds
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]]
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-- read input register
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tmr.create():alarm(7000, tmr.ALARM_AUTO, function()
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local a = mcp:readGPIO(mcp.GPA)
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if a ~= nil then
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print("GPIO A input states: " .. a)
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else
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print("GPIO A unreadable, check device")
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end
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local b = mcp:readGPIO(mcp.GPB)
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if b ~= nil then
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print("GPIO B input states: " .. b)
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else
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print("GPIO B unreadable, check device")
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end
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print(" ")
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end)
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