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/*
* Author: Jon Trulson <jtrulson@ics.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 <iostream>
#include <string>
#include <stdexcept>
#include "mpr121.h"
using namespace upm;
using namespace std;
MPR121::MPR121(int bus, uint8_t address) : m_i2c(bus)
{
m_addr = address;
mraa::Result ret = m_i2c.address(m_addr);
if (ret != mraa::SUCCESS)
{
throw std::invalid_argument(std::string(__FUNCTION__) +
": mraa_i2c_address() failed");
return;
}
m_buttonStates = 0;
m_overCurrentFault = false;
}
mraa::Result MPR121::writeBytes(uint8_t reg, uint8_t *buffer, int len)
{
if (!len || !buffer)
return mraa::SUCCESS;
// 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
for (int i=1; i<(len + 1); i++)
buf2[i] = buffer[i-1];
m_i2c.address(m_addr);
return m_i2c.write(buf2, len + 1);
}
int MPR121::readBytes(uint8_t reg, uint8_t *buffer, int len)
{
if (!len || !buffer)
return 0;
// The usual m_i2c.read() does not work here, so we need to
// read each byte individually.
for (int i=0; i<len; i++)
buffer[i] = m_i2c.readReg(reg + i);
return len;
}
bool MPR121::configAN3944()
{
// Configure the mpr121 chip as recommended in the AN3944 MPR121
// Quick Start Guide
mraa::Result rv;
// 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 ((rv = writeBytes(0x5e, &eleConf, 1)) != mraa::SUCCESS)
{
throw std::runtime_error(std::string(__FUNCTION__) +
": writeBytes(0x5e) failed");
return false;
}
// Section A
// Filtering when data is greater than baseline
// regs 0x2b-0x2e
uint8_t sectA[] = { 0x01, 0x01, 0x00, 0x00 };
if ((rv = writeBytes(0x2b, sectA, 4)) != mraa::SUCCESS)
{
throw std::runtime_error(std::string(__FUNCTION__) +
": writeBytes(0x2b) failed");
return false;
}
// Section B
// Filtering when data is less than baseline
// regs 0x2f-0x32
uint8_t sectB[] = { 0x01, 0x01, 0xff, 0x02 };
if ((rv = writeBytes(0x2f, sectB, 4)) != mraa::SUCCESS)
{
throw std::runtime_error(std::string(__FUNCTION__) +
": writeBytes(0x2f) failed");
return false;
}
// 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 ((rv = writeBytes(0x41, sectC, 24)) != mraa::SUCCESS)
{
throw std::runtime_error(std::string(__FUNCTION__) +
": writeBytes(0x41) failed");
return false;
}
// Section D
// Filter configuration
// reg 0x5d
uint8_t filterConf = 0x04;
if ((rv = writeBytes(0x5d, &filterConf, 1)) != mraa::SUCCESS)
{
throw std::runtime_error(std::string(__FUNCTION__) +
": writeBytes(0x5d) failed");
return false;
}
// Section F
// Autoconfiguration registers
// regs 0x7b-0x7f
uint8_t sectF0 = 0x0b;
if ((rv = writeBytes(0x7b, §F0, 1)) != mraa::SUCCESS)
{
throw std::runtime_error(std::string(__FUNCTION__) +
": writeBytes(0x7b) failed");
return false;
}
uint8_t sectF1[] = { 0x9c, 0x65, 0x8c };
if ((rv = writeBytes(0x7d, sectF1, 3)) != mraa::SUCCESS)
{
throw std::runtime_error(std::string(__FUNCTION__) +
": writeBytes(0x7d) failed");
return false;
}
// 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 ((rv = writeBytes(0x5e, &eleConf, 1)) != mraa::SUCCESS)
{
throw std::runtime_error(std::string(__FUNCTION__) +
": writeBytes(0x5e) failed");
return false;
}
return true;
}
void MPR121::readButtons()
{
uint8_t rv;
uint8_t buffer[2];
// read in the 2 bytes at register 0x00-0x01, and setup the member
// variables accordingly.
readBytes(0x00, buffer, 2);
m_buttonStates = (buffer[0] | ((buffer[1] & 0x1f) << 8));
if (buffer[1] & 0x80)
m_overCurrentFault = true;
else
m_overCurrentFault = false;
return;
}
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