75 lines
2.0 KiB
Lua
75 lines
2.0 KiB
Lua
---------------------------------------------------------------
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-- MPR121 I2C module for NodeMCU
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-- Based on code from: http://bildr.org/2011/05/mpr121_arduino/
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-- Tiago Custódio <tiagocustodio1@gmail.com>
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---------------------------------------------------------------
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local moduleName = ...
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local M = {}
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_G[moduleName] = M
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-- Default value for i2c communication
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local id = 0
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--device address
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local devAddr = 0
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--make it faster
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local i2c = i2c
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function M.setRegister(address, r, v)
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i2c.start(id)
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local ans = i2c.address(id, address, i2c.TRANSMITTER)
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i2c.write(id, r)
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i2c.write(id, v)
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i2c.stop(id)
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end
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function M.init(address)
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devAddr = address
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M.setRegister(devAddr, 0x5E, 0x00) -- ELE_CFG
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-- Section A - Controls filtering when data is > baseline.
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M.setRegister(devAddr, 0x2B, 0x01) -- MHD_R
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M.setRegister(devAddr, 0x2C, 0x01) -- NHD_R
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M.setRegister(devAddr, 0x2D, 0x00) -- NCL_R
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M.setRegister(devAddr, 0x2E, 0x00) -- FDL_R
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-- Section B - Controls filtering when data is < baseline.
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M.setRegister(devAddr, 0x2F, 0x01) -- MHD_F
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M.setRegister(devAddr, 0x30, 0x01) -- NHD_F
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M.setRegister(devAddr, 0x31, 0xFF) -- NCL_F
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M.setRegister(devAddr, 0x32, 0x02) -- FDL_F
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-- Section C - Sets touch and release thresholds for each electrode
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for i = 0, 11 do
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M.setRegister(devAddr, 0x41+(i*2), 0x06) -- ELE0_T
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M.setRegister(devAddr, 0x42+(i*2), 0x0A) -- ELE0_R
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end
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-- Section D - Set the Filter Configuration - Set ESI2
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M.setRegister(devAddr, 0x5D, 0x04) -- FIL_CFG
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-- Section E - Electrode Configuration - Set 0x5E to 0x00 to return to standby mode
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M.setRegister(devAddr, 0x5E, 0x0C) -- ELE_CFG
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tmr.delay(50000) -- Delay to let the electrodes settle after config
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end
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function M.readTouchInputs()
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i2c.start(id)
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i2c.address(id, devAddr, i2c.RECEIVER)
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local c = i2c.read(id, 2)
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i2c.stop(id)
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local LSB = tonumber(string.byte(c, 1))
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local MSB = tonumber(string.byte(c, 2))
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local touched = bit.lshift(MSB, 8) + LSB
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local t = {}
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for i = 0, 11 do
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t[i+1] = bit.isset(touched, i) and 1 or 0
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end
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return t
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end
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return M
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