mpr121.cpp

00001 /*
00002 Copyright (c) 2011 Anthony Buckton (abuckton [at] blackink [dot} net {dot} au)
00003  
00004 Permission is hereby granted, free of charge, to any person obtaining a copy
00005 of this software and associated documentation files (the "Software"), to deal
00006 in the Software without restriction, including without limitation the rights
00007 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008 copies of the Software, and to permit persons to whom the Software is
00009 furnished to do so, subject to the following conditions:
00010  
00011 The above copyright notice and this permission notice shall be included in
00012 all copies or substantial portions of the Software.
00013  
00014 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00020 THE SOFTWARE.
00021 */
00022 
00023 #include <mbed.h>
00024 #include <sstream>
00025 #include <string>
00026 #include <list>
00027 
00028 #include <mpr121.h>
00029     
00030 Mpr121::Mpr121(I2C *i2c, Address i2cAddress)
00031 {
00032     this->i2c = i2c;
00033     
00034     address = i2cAddress;
00035            
00036     // Configure the MPR121 settings to default
00037     this->configureSettings();
00038 }
00039 
00040    
00041 void Mpr121::configureSettings()
00042 {
00043     // Put the MPR into setup mode
00044     this->write(ELE_CFG,0x00);
00045     
00046     // Electrode filters for when data is > baseline
00047     unsigned char gtBaseline[] = {
00048          0x01,  //MHD_R
00049          0x01,  //NHD_R 
00050          0x00,  //NCL_R
00051          0x00   //FDL_R
00052          };
00053          
00054     writeMany(MHD_R,gtBaseline,4);   
00055                  
00056      // Electrode filters for when data is < baseline   
00057      unsigned char ltBaseline[] = {
00058         0x01,   //MHD_F
00059         0x01,   //NHD_F
00060         0xFF,   //NCL_F
00061         0x02    //FDL_F
00062         };
00063         
00064     writeMany(MHD_F,ltBaseline,4);
00065         
00066     // Electrode touch and release thresholds
00067     unsigned char electrodeThresholds[] = {
00068         E_THR_T, // Touch Threshhold
00069         E_THR_R  // Release Threshold
00070         };
00071 
00072     for(int i=0; i<12; i++){
00073         int result = writeMany((ELE0_T+(i*2)),electrodeThresholds,2);
00074     }   
00075 
00076     // Proximity Settings
00077     unsigned char proximitySettings[] = {
00078         0xff,   //MHD_Prox_R
00079         0xff,   //NHD_Prox_R
00080         0x00,   //NCL_Prox_R
00081         0x00,   //FDL_Prox_R
00082         0x01,   //MHD_Prox_F
00083         0x01,   //NHD_Prox_F
00084         0xFF,   //NCL_Prox_F
00085         0xff,   //FDL_Prox_F
00086         0x00,   //NHD_Prox_T
00087         0x00,   //NCL_Prox_T
00088         0x00    //NFD_Prox_T
00089         };
00090     writeMany(MHDPROXR,proximitySettings,11);
00091 
00092     unsigned char proxThresh[] = {
00093         PROX_THR_T, // Touch Threshold
00094         PROX_THR_R  // Release Threshold
00095         };
00096     writeMany(EPROXTTH,proxThresh,2); 
00097        
00098     this->write(FIL_CFG,0x04);
00099     
00100     // Set the electrode config to transition to active mode
00101     this->write(ELE_CFG,0x0c);
00102 }
00103 
00104 void Mpr121::setElectrodeThreshold(int electrode, unsigned char touch, unsigned char release){
00105     
00106     if(electrode > 11) return;
00107     
00108     // Get the current mode
00109     unsigned char mode = this->read(ELE_CFG);
00110     
00111     // Put the MPR into setup mode
00112     this->write(ELE_CFG,0x00);
00113     
00114     // Write the new threshold
00115     this->write((ELE0_T+(electrode*2)), touch);
00116     this->write((ELE0_T+(electrode*2)+1), release);
00117     
00118     //Restore the operating mode
00119     this->write(ELE_CFG, mode);
00120 }
00121     
00122     
00123 unsigned char Mpr121::read(int key){
00124 
00125     unsigned char data[2];
00126     
00127     //Start the command
00128     i2c->start();
00129 
00130     // Address the target (Write mode)
00131     int ack1= i2c->write(address);
00132 
00133     // Set the register key to read
00134     int ack2 = i2c->write(key);
00135 
00136     // Re-start for read of data
00137     i2c->start();
00138 
00139     // Re-send the target address in read mode
00140     int ack3 = i2c->write(address+1);
00141 
00142     // Read in the result
00143     data[0] = i2c->read(0); 
00144 
00145     // Reset the bus        
00146     i2c->stop();
00147 
00148     return data[0];
00149 }
00150 
00151 
00152 int Mpr121::write(int key, unsigned char value){
00153     
00154     //Start the command
00155     i2c->start();
00156 
00157     // Address the target (Write mode)
00158     int ack1= i2c->write(address);
00159 
00160     // Set the register key to write
00161     int ack2 = i2c->write(key);
00162 
00163     // Read in the result
00164     int ack3 = i2c->write(value); 
00165 
00166     // Reset the bus        
00167     i2c->stop();
00168     
00169     return (ack1+ack2+ack3)-3;
00170 }
00171 
00172 
00173 int Mpr121::writeMany(int start, unsigned char* dataSet, int length){
00174     //Start the command
00175     i2c->start();
00176 
00177     // Address the target (Write mode)
00178     int ack= i2c->write(address);
00179     if(ack!=1){
00180         return -1;
00181     }
00182     
00183     // Set the register key to write
00184     ack = i2c->write(start);
00185     if(ack!=1){
00186         return -1;
00187     }
00188 
00189     // Write the date set
00190     int count = 0;
00191     while(ack==1 && (count < length)){
00192         ack = i2c->write(dataSet[count]);
00193         count++;
00194     } 
00195     // Stop the cmd
00196     i2c->stop();
00197     
00198     return count;
00199 }
00200       
00201 
00202 bool Mpr121::getProximityMode(){
00203     if(this->read(ELE_CFG) > 0x0c)
00204         return true;
00205     else
00206         return false;
00207 }
00208 
00209 void Mpr121::setProximityMode(bool mode){
00210     this->write(ELE_CFG,0x00);
00211     if(mode){
00212         this->write(ELE_CFG,0x30); //Sense proximity from ALL pads
00213     } else {
00214         this->write(ELE_CFG,0x0c); //Sense touch, all 12 pads active.
00215     }
00216 }
00217 
00218 
00219 int Mpr121::readTouchData(){
00220     return this->read(0x00);
00221 }