/* * Author: Jon Trulson * Abhishek Malik * Copyright (c) 2014 Intel Corporation. * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #include "mpr121.h" mpr121_context mpr121_init(int bus, uint8_t address) { // make sure MRAA is initialized int mraa_rv; if ((mraa_rv = mraa_init()) != MRAA_SUCCESS) { printf("%s: mraa_init() failed (%d).\n", __FUNCTION__, mraa_rv); return NULL; } mpr121_context dev = (mpr121_context)malloc(sizeof(struct _mpr121_context)); if (!dev) return NULL; dev->bus = bus; dev->address = address; dev->i2c = mraa_i2c_init(dev->bus); if(dev->i2c == NULL){ free(dev); return NULL; } if (mraa_i2c_address(dev->i2c, dev->address) != MRAA_SUCCESS){ printf("error using i2c address: %x\n", dev->address); free(dev); return NULL; } dev->over_current_fault = false; return dev; } void mpr121_close(mpr121_context dev){ mraa_i2c_stop(dev->i2c); free(dev); } upm_result_t mpr121_write_bytes(mpr121_context dev, uint8_t reg, uint8_t *buffer, int len){ if(!len || !buffer) return UPM_ERROR_INVALID_SIZE; // create a buffer 1 byte larger than the supplied buffer, // store the register in the first byte uint8_t buf2[len + 1]; buf2[0] = reg; // copy in the buffer after the reg byte int i; for(i=1; i<(len + 1); i++) buf2[i] = buffer[i-1]; if(mraa_i2c_write(dev->i2c, buf2, len+1) != MRAA_SUCCESS){ printf("write byte error while writing\n"); return UPM_ERROR_OPERATION_FAILED; } return UPM_SUCCESS; } upm_result_t mpr121_read_bytes(mpr121_context dev, uint8_t reg, uint8_t *buffer, int len){ if(!len || !buffer) return UPM_ERROR_INVALID_SIZE; // The usual m_i2c.read() does not work here, so we need to // read each byte individually. int i; for (i=0; ii2c, reg+i); return UPM_SUCCESS; } upm_result_t mpr121_read_buttons(mpr121_context dev, uint32_t* states, int num){ int len = 2; uint8_t buffer[2]; // read in the 2 bytes at register 0x00-0x01, and setup the member // variables accordingly. mpr121_read_bytes(dev, 0x00, buffer, len); *states = (buffer[0] | ((buffer[1] & 0x1f) << 8)); if (buffer[1] & 0x80) dev->over_current_fault = true; else dev->over_current_fault = false; return UPM_SUCCESS; } upm_result_t mpr121_config_an3944(mpr121_context dev){ // Configure the mpr121 chip as recommended in the AN3944 MPR121 // Quick Start Guide // First, turn off all electrodes by zeroing out the Electrode Configuration // register. // If this one fails, it's unlikely any of the others will succeed. uint8_t eleConf = 0x00; if (mpr121_write_bytes(dev, 0x5e, &eleConf, 1) != UPM_SUCCESS){ printf("write to electrode configuration register failed\n"); return UPM_ERROR_OPERATION_FAILED; } // Section A // Filtering when data is greater than baseline // regs 0x2b-0x2e uint8_t sectA[] = {0x01, 0x01, 0x00, 0x00}; if (mpr121_write_bytes(dev, 0x2b, sectA, 4) != UPM_SUCCESS){ printf("write to section a failed\n"); return UPM_ERROR_OPERATION_FAILED; } // Section B // Filtering when data is less than baseline // regs 0x2f-0x32 uint8_t sectB[] = {0x01, 0x01, 0xff, 0x02}; if (mpr121_write_bytes(dev, 0x2f, sectB, 4) != UPM_SUCCESS){ printf("write to section b failed\n"); return UPM_ERROR_OPERATION_FAILED; } // Section C // Touch Threshold/Release registers, ELE0-ELE11 // regs 0x41-0x58 // __T_ __R_ uint8_t sectC[] = {0x0f, 0x0a, 0x0f, 0x0a, 0x0f, 0x0a, 0x0f, 0x0a, 0x0f, 0x0a, 0x0f, 0x0a, 0x0f, 0x0a, 0x0f, 0x0a, 0x0f, 0x0a, 0x0f, 0x0a, 0x0f, 0x0a, 0x0f, 0x0a}; if (mpr121_write_bytes(dev, 0x41, sectC, 24) != UPM_SUCCESS){ printf("failed to configure touch threshold/release regs\n"); return UPM_ERROR_OPERATION_FAILED; } // Section D // Filter configuration // reg 0x5d uint8_t filterConf = 0x04; if (mpr121_write_bytes(dev, 0x5d, &filterConf, 1) != UPM_SUCCESS){ printf("unable to configure filters\n"); return UPM_ERROR_OPERATION_FAILED; } // Section F // Autoconfiguration registers // regs 0x7b-0x7f uint8_t sectF0 = 0x0b; if (mpr121_write_bytes(dev, 0x7b, §F0, 1) != UPM_SUCCESS){ printf("unable to configure auto config regs\n"); return UPM_ERROR_OPERATION_FAILED; } uint8_t sectF1[] = {0x9c, 0x65, 0x8c}; if (mpr121_write_bytes(dev, 0x7d, sectF1, 3) != UPM_SUCCESS){ return UPM_ERROR_OPERATION_FAILED; } // Section E - this one must be set last, and switches to run mode // Enable all 12 electrodes, and set a pre-calibration to avoid // excessive calibration delay on startup. // reg 0x5e eleConf = 0x8c; if (mpr121_write_bytes(dev, 0x5e, &eleConf, 3) != UPM_SUCCESS){ return UPM_ERROR_OPERATION_FAILED; } return UPM_SUCCESS; }