comparison projects/mpr121/I2C_MPR121.cpp @ 268:8d80eda512cd prerelease

Added new overlay for using PRU0 or PRU1, a script to halt board on button press, and several example projects

+/*
+ * I2C_MPR121.cpp
+ *
+ *  Created on: Oct 14, 2013
+ *      Author: Victor Zappi
+ */
+
+
+#include "I2C_MPR121.h"
+
+I2C_MPR121::I2C_MPR121() {
+
+}
+
+boolean I2C_MPR121::begin(uint8_t bus, uint8_t i2caddr) {
+  _i2c_address = i2caddr;
+	
+  if(initI2C_RW(bus, i2caddr, 0) > 0)
+	  return false;
+
+  // soft reset
+  writeRegister(MPR121_SOFTRESET, 0x63);
+  usleep(1000);
+  //delay(1);
+  for (uint8_t i=0; i<0x7F; i++) {
+  //  Serial.print("$"); Serial.print(i, HEX); 
+  //  Serial.print(": 0x"); Serial.println(readRegister8(i));
+  }
+  
+
+  writeRegister(MPR121_ECR, 0x0);
+
+  uint8_t c = readRegister8(MPR121_CONFIG2);
+  
+  if (c != 0x24) {
+	  rt_printf("MPR121 read 0x%x instead of 0x24\n", c);
+	  return false;
+  }
+
+  setThresholds(12, 6);
+  writeRegister(MPR121_MHDR, 0x01);
+  writeRegister(MPR121_NHDR, 0x01);
+  writeRegister(MPR121_NCLR, 0x0E);
+  writeRegister(MPR121_FDLR, 0x00);
+
+  writeRegister(MPR121_MHDF, 0x01);
+  writeRegister(MPR121_NHDF, 0x05);
+  writeRegister(MPR121_NCLF, 0x01);
+  writeRegister(MPR121_FDLF, 0x00);
+
+  writeRegister(MPR121_NHDT, 0x00);
+  writeRegister(MPR121_NCLT, 0x00);
+  writeRegister(MPR121_FDLT, 0x00);
+
+  writeRegister(MPR121_DEBOUNCE, 0);
+  writeRegister(MPR121_CONFIG1, 0x10); // default, 16uA charge current
+  writeRegister(MPR121_CONFIG2, 0x20); // 0.5uS encoding, 1ms period
+
+//  writeRegister(MPR121_AUTOCONFIG0, 0x8F);
+
+//  writeRegister(MPR121_UPLIMIT, 150);
+//  writeRegister(MPR121_TARGETLIMIT, 100); // should be ~400 (100 shifted)
+//  writeRegister(MPR121_LOWLIMIT, 50);
+  // enable all electrodes
+  writeRegister(MPR121_ECR, 0x8F);  // start with first 5 bits of baseline tracking
+
+  return true;
+}
+
+void I2C_MPR121::setThresholds(uint8_t touch, uint8_t release) {
+  for (uint8_t i=0; i<12; i++) {
+    writeRegister(MPR121_TOUCHTH_0 + 2*i, touch);
+    writeRegister(MPR121_RELEASETH_0 + 2*i, release);
+  }
+}
+
+uint16_t  I2C_MPR121::filteredData(uint8_t t) {
+  if (t > 12) return 0;
+  return readRegister16(MPR121_FILTDATA_0L + t*2);
+}
+
+uint16_t  I2C_MPR121::baselineData(uint8_t t) {
+  if (t > 12) return 0;
+  uint16_t bl = readRegister8(MPR121_BASELINE_0 + t);
+  return (bl << 2);
+}
+
+uint16_t  I2C_MPR121::touched(void) {
+  uint16_t t = readRegister16(MPR121_TOUCHSTATUS_L);
+  return t & 0x0FFF;
+}
+
+/*********************************************************************/
+
+
+uint8_t I2C_MPR121::readRegister8(uint8_t reg) {
+    unsigned char inbuf, outbuf;
+    struct i2c_rdwr_ioctl_data packets;
+    struct i2c_msg messages[2];
+
+    /*
+     * In order to read a register, we first do a "dummy write" by writing
+     * 0 bytes to the register we want to read from.  This is similar to
+     * the packet in set_i2c_register, except it's 1 byte rather than 2.
+     */
+    outbuf = reg;
+    messages[0].addr  = 0x5A;
+    messages[0].flags = 0;
+    messages[0].len   = sizeof(outbuf);
+    messages[0].buf   = &outbuf;
+
+    /* The data will get returned in this structure */
+    messages[1].addr  = 0x5A;
+    messages[1].flags = I2C_M_RD/* | I2C_M_NOSTART*/;
+    messages[1].len   = sizeof(inbuf);
+    messages[1].buf   = &inbuf;
+
+    /* Send the request to the kernel and get the result back */
+    packets.msgs      = messages;
+    packets.nmsgs     = 2;
+    if(ioctl(i2C_file, I2C_RDWR, &packets) < 0) {
+        rt_printf("Unable to send data");
+        return 0;
+    }
+
+    return inbuf;
+}
+
+uint16_t I2C_MPR121::readRegister16(uint8_t reg) {
+    unsigned char inbuf[2], outbuf;
+    struct i2c_rdwr_ioctl_data packets;
+    struct i2c_msg messages[2];
+
+    /*
+     * In order to read a register, we first do a "dummy write" by writing
+     * 0 bytes to the register we want to read from.  This is similar to
+     * the packet in set_i2c_register, except it's 1 byte rather than 2.
+     */
+    outbuf = reg;
+    messages[0].addr  = _i2c_address;
+    messages[0].flags = 0;
+    messages[0].len   = sizeof(outbuf);
+    messages[0].buf   = &outbuf;
+
+    /* The data will get returned in this structure */
+    messages[1].addr  = _i2c_address;
+    messages[1].flags = I2C_M_RD/* | I2C_M_NOSTART*/;
+    messages[1].len   = sizeof(inbuf);
+    messages[1].buf   = inbuf;
+
+    /* Send the request to the kernel and get the result back */
+    packets.msgs      = messages;
+    packets.nmsgs     = 2;
+    if(ioctl(i2C_file, I2C_RDWR, &packets) < 0) {
+        rt_printf("Unable to send data");
+        return 0;
+    }
+
+    return (uint16_t)inbuf[0] | (((uint16_t)inbuf[1]) << 8);
+}
+
+/**************************************************************************/
+/*!
+    @brief  Writes 8-bits to the specified destination register
+*/
+/**************************************************************************/
+void I2C_MPR121::writeRegister(uint8_t reg, uint8_t value) {
+	uint8_t buf[2] = { reg, value };
+
+	if(write(i2C_file, buf, 2) != 2)
+	{
+		cout << "Failed to write register " << (int)reg << " on MPR121\n";
+		return;
+	}
+}
+