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     
00038     this->configureSettings();
00039 }
00040 
00041    
00042 void Mpr121::configureSettings()
00043 {
00044     // Put the MPR into setup mode
00045     this->write(ELE_CFG,0x00);
00046     
00047     // Electrode filters for when data is > baseline
00048     unsigned char gtBaseline[] = {
00049          0x01,  //MHD_R
00050          0x01,  //NHD_R 
00051          0x00,  //NCL_R
00052          0x00   //FDL_R
00053          };
00054          
00055     writeMany(MHD_R,gtBaseline,4);   
00056                  
00057      // Electrode filters for when data is < baseline   
00058      unsigned char ltBaseline[] = {
00059         0x01,   //MHD_F
00060         0x01,   //NHD_F
00061         0xFF,   //NCL_F
00062         0x02    //FDL_F
00063         };
00064         
00065     writeMany(MHD_F,ltBaseline,4);
00066         
00067     // Electrode touch and release thresholds
00068     unsigned char electrodeThresholds[] = {
00069         E_THR_T, // Touch Threshhold
00070         E_THR_R  // Release Threshold
00071         };
00072 
00073     for(int i=0; i<12; i++){
00074         int result = writeMany((ELE0_T+(i*2)),electrodeThresholds,2);
00075     }   
00076 
00077     // Proximity Settings
00078     unsigned char proximitySettings[] = {
00079         0xff,   //MHD_Prox_R
00080         0xff,   //NHD_Prox_R
00081         0x00,   //NCL_Prox_R
00082         0x00,   //FDL_Prox_R
00083         0x01,   //MHD_Prox_F
00084         0x01,   //NHD_Prox_F
00085         0xFF,   //NCL_Prox_F
00086         0xff,   //FDL_Prox_F
00087         0x00,   //NHD_Prox_T
00088         0x00,   //NCL_Prox_T
00089         0x00    //NFD_Prox_T
00090         };
00091     writeMany(MHDPROXR,proximitySettings,11);
00092 
00093     unsigned char proxThresh[] = {
00094         PROX_THR_T, // Touch Threshold
00095         PROX_THR_R  // Release Threshold
00096         };
00097     writeMany(EPROXTTH,proxThresh,2); 
00098        
00099     this->write(FIL_CFG,0x04);
00100     
00101     // Set the electrode config to transition to active mode
00102     this->write(ELE_CFG,0x0c);
00103 }
00104 
00105 void Mpr121::setElectrodeThreshold(int electrode, unsigned char touch, unsigned char release){
00106     
00107     if(electrode > 11) return;
00108     
00109     // Get the current mode
00110     unsigned char mode = this->read(ELE_CFG);
00111     
00112     // Put the MPR into setup mode
00113     this->write(ELE_CFG,0x00);
00114     
00115     // Write the new threshold
00116     this->write((ELE0_T+(electrode*2)), touch);
00117     this->write((ELE0_T+(electrode*2)+1), release);
00118     
00119     //Restore the operating mode
00120     this->write(ELE_CFG, mode);
00121 }
00122     
00123     
00124 unsigned char Mpr121::read(int key){
00125 
00126     unsigned char data[2];
00127     
00128     //Start the command
00129     i2c->start();
00130 
00131     // Address the target (Write mode)
00132     int ack1= i2c->write(address);
00133 
00134     // Set the register key to read
00135     int ack2 = i2c->write(key);
00136 
00137     // Re-start for read of data
00138     i2c->start();
00139 
00140     // Re-send the target address in read mode
00141     int ack3 = i2c->write(address+1);
00142 
00143     // Read in the result
00144     data[0] = i2c->read(0); 
00145 
00146     // Reset the bus        
00147     i2c->stop();
00148 
00149     return data[0];
00150 }
00151 
00152 
00153 int Mpr121::write(int key, unsigned char value){
00154     
00155     //Start the command
00156     i2c->start();
00157 
00158     // Address the target (Write mode)
00159     int ack1= i2c->write(address);
00160 
00161     // Set the register key to write
00162     int ack2 = i2c->write(key);
00163 
00164     // Read in the result
00165     int ack3 = i2c->write(value); 
00166 
00167     // Reset the bus        
00168     i2c->stop();
00169     
00170     return (ack1+ack2+ack3)-3;
00171 }
00172 
00173 
00174 int Mpr121::writeMany(int start, unsigned char* dataSet, int length){
00175     //Start the command
00176     i2c->start();
00177 
00178     // Address the target (Write mode)
00179     int ack= i2c->write(address);
00180     if(ack!=1){
00181         return -1;
00182     }
00183     
00184     // Set the register key to write
00185     ack = i2c->write(start);
00186     if(ack!=1){
00187         return -1;
00188     }
00189 
00190     // Write the date set
00191     int count = 0;
00192     while(ack==1 && (count < length)){
00193         ack = i2c->write(dataSet[count]);
00194         count++;
00195     } 
00196     // Stop the cmd
00197     i2c->stop();
00198     
00199     return count;
00200 }
00201       
00202 
00203 bool Mpr121::getProximityMode(){
00204     if(this->read(ELE_CFG) > 0x0c)
00205         return true;
00206     else
00207         return false;
00208 }
00209 
00210 void Mpr121::setProximityMode(bool mode){
00211     this->write(ELE_CFG,0x00);
00212     if(mode){
00213         this->write(ELE_CFG,0x30); //Sense proximity from ALL pads
00214     } else {
00215         this->write(ELE_CFG,0x0c); //Sense touch, all 12 pads active.
00216     }
00217 }
00218 
00219 
00220 int Mpr121::readTouchData(){
00221     return this->read(0x00);
00222 }