use mbed os
Dependents: Seeed_Grove_I2C_Touch_Example
Fork of MPR121 by
MPR121.cpp
- Committer:
- sam_grove
- Date:
- 2013-03-07
- Revision:
- 1:cee45334b36a
- Parent:
- 0:42add775212a
- Child:
- 2:4c0d4b90a3ed
File content as of revision 1:cee45334b36a:
/** * @file MPR121.cpp * @brief Device driver - MPR121 capactiive touch IC * @author sam grove * @version 1.0 * @see http://cache.freescale.com/files/sensors/doc/data_sheet/MPR121.pdf * * Copyright (c) 2013 * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include "MPR121.h" MPR121::MPR121(I2C &i2c, InterruptIn &pin, MPR121_ADDR i2c_addr) { _i2c = &i2c; _irq = &pin; _i2c_addr = (i2c_addr << 1); return; } void MPR121::init(void) { uint8_t i = 0; // set the i2c speed _i2c->frequency(400000); // irq is open-collector and active-low _irq->mode(PullUp); // setup and registers - start with POR values (must be in stop mode) MPR121::writeRegister(SRST, 0x63); //REG 0x80 // baseline < filtered data = touch (set by auto-config) // for(i=0; i<12; i++) // { // MPR121::writeRegister(E0BV+i, 0x10); //REG 0x1E...0x29 // } // Baseline Filtering Control Register (changes response sensitivity) // http://cache.freescale.com/files/sensors/doc/app_note/AN3891.pdf MPR121::writeRegister(MHDR, 0x1); //REG 0x2B MPR121::writeRegister(NHDR, 0x1); //REG 0x2C MPR121::writeRegister(NCLR, 0x0); //REG 0x2D MPR121::writeRegister(FDLR, 0x0); //REG 0x2E MPR121::writeRegister(MHDF, 0x1); //REG 0x2F MPR121::writeRegister(NHDF, 0x1); //REG 0x30 MPR121::writeRegister(NCLF, 0xFF); //REG 0x31 MPR121::writeRegister(FDLF, 0x2); //REG 0x32 // Touch / Release Threshold // cache.freescale.com/files/sensors/doc/app_note/AN3892.pdf for(i=0; i<(12*2); i+=2) // touch { MPR121::writeRegister(E0TTH+i, 0x20); //REG 0x41...0x58 odd } for(i=0; i<(12*2); i+=2) // release { MPR121::writeRegister(E0RTH+i, 0x10); //REG 0x41...0x58 even } // Debounce Register DR=b6...4, DT=b2...0 MPR121::writeRegister(DT_DR, 0x11); //REG 0x5B // Filter and Global CDC CDT Configuration (sample time, charge current) MPR121::writeRegister(CDC_CONFIG, 0x10); //REG 0x5C default 10 MPR121::writeRegister(CDT_CONFIG, 0x20); //REG 0x5D default 24 // Electrode Charge Current Register - uses CDC_STAT if 0 // for(i=0; i<12; i++) // current // { // MPR121::writeRegister(CDC0+i, 0x10); //REG 0x5F ... 0x6B // } // for(i=0; i<6; i++) // time // { // MPR121::writeRegister(CDT0_CDT1+i, 0x11); //REG 0x6C ... 0x72 // } // Auto-Configuration Registers // http://cache.freescale.com/files/sensors/doc/app_note/AN3889.pdf MPR121::writeRegister(AUTO_CFG0, 0x33); // REG 0x7B MPR121::writeRegister(AUTO_CFG1, 0x07); // REG 0x7C MPR121::writeRegister(USL, 0xc9); // REG 0x7D((3.3-.07)/3.3) * 256 MPR121::writeRegister(LSL, 0x83); // REG 0x7E((3.3-.07)/3.3) * 256 * 0.65f MPR121::writeRegister(TL, 0xb5); // REG 0x7F((3.3-.07)/3.3) * 256 * 0.9f // 255 > USL > TL > LSL > 0 // MPR121::registerDump(); // Electrode Configuration Register - enable all 12 and start MPR121::writeRegister(ECR, 0x8f); return; } void MPR121::enable(void) { _button = 0; _button_has_changed = 0; // enable the 12 electrodes - allow disable to put device into // lower current consumption mode MPR121::writeRegister(ECR, 0x8f); // and attach the interrupt handler _irq->fall(this, &MPR121::handler); return; } void MPR121::disable(void) { // detach the interrupt handler _irq->fall(NULL); _button = 0; _button_has_changed = 0; // put the device in low current consumption mode - dont re-init registers MPR121::writeRegister(ECR, 0x0); MPR121::writeRegister(AUTO_CFG0, 0x0); // REG 0x7B MPR121::writeRegister(AUTO_CFG1, 0x0); // REG 0x7C return; } uint32_t MPR121::isPressed(void) { return _button_has_changed; } uint16_t MPR121::buttonPressed(void) { _button_has_changed = 0; return _button; } void MPR121::registerDump(void) const { uint8_t reg_val = 0; for(int i=0; i<0x80; i++) { reg_val = MPR121::readRegister(i); printf("Reg 0x%02x: 0x%02x \n", i, reg_val); } return; } void MPR121::handler(void) { uint16_t reg_val = 0, oor_val = 0; // read register 0 and 1 reg_val = MPR121::readRegister(ELE0_7_STAT); reg_val |= MPR121::readRegister(ELE8_11_STAT) << 8; // 2 and 3 oor_val = MPR121::readRegister(ELE0_7_OOR_STAT); oor_val |= MPR121::readRegister(ELE8_11_OOR_STAT) << 8; if(0 != oor_val) { error("%s %d: MPR121 OOR failure - 0x%04x\n", __FILE__, __LINE__, oor_val); } _button = reg_val; _button_has_changed = 1; return; } void MPR121::writeRegister(uint8_t const reg, uint8_t const data) const { char buf[2] = {reg, data}; uint8_t result = 0; __disable_irq(); // Tickers and other timebase events can jack up the I2C bus result = _i2c->write(_i2c_addr, buf, 2); __enable_irq(); // Just need to block during the transaction if(0 != result) { error("%s %d: I2c write failed\n", __FILE__, __LINE__); } return; } uint8_t MPR121::readRegister(uint8_t const reg) const { uint8_t result = 1, data = 0; __disable_irq(); // Tickers and other timebase events can jack up the I2C bus _i2c->start(); result &= _i2c->write(_i2c_addr); result &= _i2c->write(reg); // issue a repeated start... _i2c->start(); result &= _i2c->write(_i2c_addr | 0x01); // read with nak data = _i2c->read(0); _i2c->stop(); __enable_irq(); // Just need to block during the transaction if(1 != result) { error("%s %d: I2C read failed\n", __FILE__, __LINE__); } return data; }