47 lines
1.5 KiB
Lua
47 lines
1.5 KiB
Lua
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---
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-- @description Shows control of 8 GPIO pins/LEDs via I2C with the MCP23008 I/O expander.
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-- Tested on odeMCU 0.9.5 build 20150213.
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-- @date March 02, 2015
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-- @circuit Connect 8 LEDs withs resistors to the GPIO pins of the MCP23008.
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-- Connect GPIO0 of the ESP8266-01 module to the SCL pin of the MCP23008.
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-- Connect GPIO2 of the ESP8266-01 module to the SDA pin of the MCP23008.
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-- Connect two 4.7k pull-up resistors on SDA and SCL
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-- Use 3.3V for VCC.
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-- @author Miguel (AllAboutEE)
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-- GitHub: https://github.com/AllAboutEE
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-- Working Example Video: https://www.youtube.com/watch?v=KphAJMZZed0
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-- Website: http://AllAboutEE.com
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---------------------------------------------------------------------------------------------
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local mcp23008 = require ("mcp23008")
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-- ESP-01 GPIO Mapping as per GPIO Table in https://github.com/nodemcu/nodemcu-firmware
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local gpio0, gpio2 = 3, 4
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---
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-- @name count()
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-- @description Reads the value from the GPIO register, increases the read value by 1
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-- and writes it back so the LEDs will display a binary count up to 255 or 0xFF in hex.
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local function count()
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local gpio = mcp23008.readGPIO()
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if(gpio<0xff) then
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mcp23008.writeGPIO(gpio+1)
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else
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mcp23008.writeGPIO(0x00)
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end
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end
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do
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-- Setup MCP23008
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mcp23008.begin(0x0,gpio2,gpio0,i2c.SLOW)
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mcp23008.writeIODIR(0x00) -- make all GPIO pins as outputs
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mcp23008.writeGPIO(0x00) -- make all GIPO pins off/low
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-- Run count() every 100ms
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tmr.create():alarm(100, tmr.ALARM_AUTO, count)
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end
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