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MPR121: Added C Source

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Signed-off-by: Abhishek Malik <abhishek.malik@intel.com>
This commit is contained in:
Abhishek Malik
2016-09-09 19:12:25 -07:00
committed by Noel Eck
parent e0e93281fb
commit 25f4cb0be1
4 changed files with 400 additions and 5 deletions
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src/mpr121/mpr121.c Normal file
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/*
* Author: Jon Trulson <jtrulson@ics.com>
* Abhishek Malik <abhishek.malik@intel.com>
* 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){
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){
free(dev);
printf("error using i2c address: %x\n", dev->address);
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_address(dev->i2c, dev->address) != MRAA_SUCCESS){
printf("write byte error address\n");
return UPM_ERROR_OPERATION_FAILED;
}
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; i<len; i++)
buffer[i] = mraa_i2c_read_byte_data(dev->i2c, 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, &sectF0, 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;
}