Alvaro Cassinelli / Mbed 2 deprecated laserUI

Laser Sensing Display for UI interfaces in the real world

Dependencies:   mbed

Fork of skinGames_forktest by Alvaro Cassinelli

hardwareIO/lockin.cpp@0:345b3bc7a0ea, 2012-03-28 (annotated)

Committer:
mbedalvaro
Date:
Wed Mar 28 14:40:01 2012 +0000
Revision:
0:345b3bc7a0ea
Child:
10:6f8e48dca1bd
This version (using rigid frame, base and child classes, etc) works, but the blob is strangely smaller. Need to check this.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbedalvaro 0:345b3bc7a0ea 1 #include "lockin.h"
mbedalvaro 0:345b3bc7a0ea 2
mbedalvaro 0:345b3bc7a0ea 3 Lockin lockin=Lockin();//pre-instanciation of object lockin with inter-file scope (declared extern in .h file)
mbedalvaro 0:345b3bc7a0ea 4
mbedalvaro 0:345b3bc7a0ea 5 void catchInterupt(uint32_t value){
mbedalvaro 0:345b3bc7a0ea 6 lockin.buffer_pos=(lockin.buffer_pos+1)%BUFFER_SIZE;
mbedalvaro 0:345b3bc7a0ea 7 lockin.buffer[lockin.buffer_pos] = (value>>4)&0xFFF; // this is 12 bit precision ADC (0 to 4095)
mbedalvaro 0:345b3bc7a0ea 8 }
mbedalvaro 0:345b3bc7a0ea 9
mbedalvaro 0:345b3bc7a0ea 10 // PWM generation is configure as double edge
mbedalvaro 0:345b3bc7a0ea 11 // MR0 (Match Register 0) control the frequency
mbedalvaro 0:345b3bc7a0ea 12 // 'pwm2' uses MR1 and MR2 (rising and falling edges)
mbedalvaro 0:345b3bc7a0ea 13 // 'pwm4' uses MR3 and MR4 (rising and falling edges)
mbedalvaro 0:345b3bc7a0ea 14 // 'pwm1' and 'pwm3' cannot be used since they share the same Match Register
mbedalvaro 0:345b3bc7a0ea 15 // for the moment, all PWM pin are set as output:
mbedalvaro 0:345b3bc7a0ea 16 PwmOut pwm1(p26);
mbedalvaro 0:345b3bc7a0ea 17 PwmOut pwm2(p25); //also defined as LOCKIN_LASER_PIN
mbedalvaro 0:345b3bc7a0ea 18 PwmOut pwm3(p24);
mbedalvaro 0:345b3bc7a0ea 19 PwmOut pwm4(p23); //also defined as LOCKIN_REF_PIN
mbedalvaro 0:345b3bc7a0ea 20 PwmOut pwm5(p22);
mbedalvaro 0:345b3bc7a0ea 21 PwmOut pwm6(p21);
mbedalvaro 0:345b3bc7a0ea 22
mbedalvaro 0:345b3bc7a0ea 23 //Lockin::Lockin(){}
mbedalvaro 0:345b3bc7a0ea 24
mbedalvaro 0:345b3bc7a0ea 25 void Lockin::init(){
mbedalvaro 0:345b3bc7a0ea 26
mbedalvaro 0:345b3bc7a0ea 27 //configure PWM for the laser and the Lockin
mbedalvaro 0:345b3bc7a0ea 28 refFreq = 147;
mbedalvaro 0:345b3bc7a0ea 29 offsetRef = 40;
mbedalvaro 0:345b3bc7a0ea 30 halfRefFreq = refFreq / 2;
mbedalvaro 0:345b3bc7a0ea 31
mbedalvaro 0:345b3bc7a0ea 32 refFrequency = 653; //init the lock-in frequency at 653 kHz
mbedalvaro 0:345b3bc7a0ea 33 phaseShiftLaser = 0.546; //offset of 54% for the laser signal
mbedalvaro 0:345b3bc7a0ea 34 phaseShiftLockin = 0; //no offset for the lock-in reference
mbedalvaro 0:345b3bc7a0ea 35 initPWM();
mbedalvaro 0:345b3bc7a0ea 36
mbedalvaro 0:345b3bc7a0ea 37 //configure ADC:
mbedalvaro 0:345b3bc7a0ea 38 clearBuffer();
mbedalvaro 0:345b3bc7a0ea 39
mbedalvaro 0:345b3bc7a0ea 40 adc.startmode(0,0);
mbedalvaro 0:345b3bc7a0ea 41 adc.burst(1);
mbedalvaro 0:345b3bc7a0ea 42 adc.setup(LOCKIN_ADC_PIN, 1);
mbedalvaro 0:345b3bc7a0ea 43 adc.select(LOCKIN_ADC_PIN);
mbedalvaro 0:345b3bc7a0ea 44 adc.interrupt_state(LOCKIN_ADC_PIN, 1);
mbedalvaro 0:345b3bc7a0ea 45 adc.append(LOCKIN_ADC_PIN, catchInterupt);
mbedalvaro 0:345b3bc7a0ea 46 }
mbedalvaro 0:345b3bc7a0ea 47
mbedalvaro 0:345b3bc7a0ea 48
mbedalvaro 0:345b3bc7a0ea 49 void Lockin::initPWM(){
mbedalvaro 0:345b3bc7a0ea 50
mbedalvaro 0:345b3bc7a0ea 51 float halfPeriod = 0.5 * MBEDFREQUENCY / refFrequency; // half shared periof
mbedalvaro 0:345b3bc7a0ea 52 _currentMR[0] = int(1.0 * MBEDFREQUENCY / refFrequency); //save the current value of MR0 (shared periof) //147
mbedalvaro 0:345b3bc7a0ea 53 _currentMR[1] = int(phaseShiftLaser * halfPeriod); //save the current value of MR1 //40
mbedalvaro 0:345b3bc7a0ea 54 _currentMR[2] = int(_currentMR[1] + halfPeriod); //save the current value of MR2 //40+73
mbedalvaro 0:345b3bc7a0ea 55 _currentMR[3] = int(phaseShiftLockin * halfPeriod); //save the current value of MR1 //0
mbedalvaro 0:345b3bc7a0ea 56 _currentMR[4] = int(_currentMR[3] + halfPeriod); //save the current value of MR2 //73
mbedalvaro 0:345b3bc7a0ea 57
mbedalvaro 0:345b3bc7a0ea 58
mbedalvaro 0:345b3bc7a0ea 59 // set PWM:
mbedalvaro 0:345b3bc7a0ea 60 LPC_PWM1->TCR = (1 << 1); // Reset counter, disable PWM
mbedalvaro 0:345b3bc7a0ea 61 LPC_SC->PCLKSEL0 &= ~(0x3 << 12);
mbedalvaro 0:345b3bc7a0ea 62 LPC_SC->PCLKSEL0 |= (1 << 12); // Set peripheral clock divider to /1, i.e. system clock
mbedalvaro 0:345b3bc7a0ea 63
mbedalvaro 0:345b3bc7a0ea 64 LPC_PWM1->PCR |= 0x0014; // Double edge PWM for PWM2,4
mbedalvaro 0:345b3bc7a0ea 65
mbedalvaro 0:345b3bc7a0ea 66 LPC_PWM1->MR0 = _currentMR[0]; // Match Register 0 is shared period counter for all PWM1
mbedalvaro 0:345b3bc7a0ea 67
mbedalvaro 0:345b3bc7a0ea 68 LPC_PWM1->MR1 = _currentMR[1]; // Match Register 1 is laser rising edge counter
mbedalvaro 0:345b3bc7a0ea 69 LPC_PWM1->MR2 = _currentMR[2]; // Match Register 2 is laser falling edge counter
mbedalvaro 0:345b3bc7a0ea 70 LPC_PWM1->MR3 = _currentMR[3]; // Match Register 3 is lock-in rising edge counter
mbedalvaro 0:345b3bc7a0ea 71 LPC_PWM1->MR4 = _currentMR[4]; // Match Register 4 is lock-in falling edge counter
mbedalvaro 0:345b3bc7a0ea 72
mbedalvaro 0:345b3bc7a0ea 73 LPC_PWM1->LER |= 1; // Start updating at next period start
mbedalvaro 0:345b3bc7a0ea 74 LPC_PWM1->TCR = (1 << 0) || (1 << 3); // Enable counter and PWM
mbedalvaro 0:345b3bc7a0ea 75 }
mbedalvaro 0:345b3bc7a0ea 76
mbedalvaro 0:345b3bc7a0ea 77 //change the frequency of the PWM after initPWM()
mbedalvaro 0:345b3bc7a0ea 78 void Lockin::setPWMFrequency(float freq){
mbedalvaro 0:345b3bc7a0ea 79 refFrequency = freq;
mbedalvaro 0:345b3bc7a0ea 80 _currentMR[0] = int(MBEDFREQUENCY / refFrequency); //save the current value of MR0
mbedalvaro 0:345b3bc7a0ea 81 LPC_PWM1->MR0 = _currentMR[0]; //update PWM shared period register
mbedalvaro 0:345b3bc7a0ea 82 LPC_PWM1->LER |= 1; //update PWM
mbedalvaro 0:345b3bc7a0ea 83 }
mbedalvaro 0:345b3bc7a0ea 84
mbedalvaro 0:345b3bc7a0ea 85 //change the phase shift of the sensing laser after initPWM()
mbedalvaro 0:345b3bc7a0ea 86 void Lockin::setLaserPhaseShift(float phaseShift){
mbedalvaro 0:345b3bc7a0ea 87 phaseShiftLaser = phaseShift;
mbedalvaro 0:345b3bc7a0ea 88 float halfPeriod = 0.5 * MBEDFREQUENCY / refFrequency;
mbedalvaro 0:345b3bc7a0ea 89 _currentMR[1] = int(phaseShiftLaser * halfPeriod); //save the current value of MR1
mbedalvaro 0:345b3bc7a0ea 90 _currentMR[2] = _currentMR[1] + halfPeriod; //save the current value of MR2
mbedalvaro 0:345b3bc7a0ea 91
mbedalvaro 0:345b3bc7a0ea 92 LPC_PWM1->MR1 = _currentMR[1]; //update Laser rising edge match register
mbedalvaro 0:345b3bc7a0ea 93 LPC_PWM1->MR2 = _currentMR[2]; //update Laser faling edge match register
mbedalvaro 0:345b3bc7a0ea 94 }
mbedalvaro 0:345b3bc7a0ea 95
mbedalvaro 0:345b3bc7a0ea 96 //change the phase shift of the lock-in after initPWM()
mbedalvaro 0:345b3bc7a0ea 97 void Lockin::setLockinPhaseShift(float phaseShift){
mbedalvaro 0:345b3bc7a0ea 98 phaseShiftLockin = phaseShift;
mbedalvaro 0:345b3bc7a0ea 99 float halfPeriod = 0.5 * MBEDFREQUENCY / refFrequency;
mbedalvaro 0:345b3bc7a0ea 100 _currentMR[3] = int(phaseShiftLockin * halfPeriod); //save the current value of MR1
mbedalvaro 0:345b3bc7a0ea 101 _currentMR[4] = _currentMR[3] + halfPeriod; //save the current value of MR2
mbedalvaro 0:345b3bc7a0ea 102
mbedalvaro 0:345b3bc7a0ea 103 LPC_PWM1->MR3 = _currentMR[3]; //update lock-in rising edge match register
mbedalvaro 0:345b3bc7a0ea 104 LPC_PWM1->MR4 = _currentMR[4]; //update lock-in faling edge match register
mbedalvaro 0:345b3bc7a0ea 105 }
mbedalvaro 0:345b3bc7a0ea 106
mbedalvaro 0:345b3bc7a0ea 107
mbedalvaro 0:345b3bc7a0ea 108 void Lockin::setLaserPower(bool power){
mbedalvaro 0:345b3bc7a0ea 109 if(power){
mbedalvaro 0:345b3bc7a0ea 110 LPC_PWM1->MR1 = _currentMR[1];
mbedalvaro 0:345b3bc7a0ea 111 LPC_PWM1->MR2 = _currentMR[2];
mbedalvaro 0:345b3bc7a0ea 112 LPC_PWM1->LER |= 1; // update PWM at the next period
mbedalvaro 0:345b3bc7a0ea 113 }
mbedalvaro 0:345b3bc7a0ea 114 else{
mbedalvaro 0:345b3bc7a0ea 115 LPC_PWM1->MR1 = 0; //set rising edge at 0
mbedalvaro 0:345b3bc7a0ea 116 LPC_PWM1->MR2 = 0; //set falling edge at 0
mbedalvaro 0:345b3bc7a0ea 117 LPC_PWM1->LER |= 1; // update PWM at the next period
mbedalvaro 0:345b3bc7a0ea 118 }
mbedalvaro 0:345b3bc7a0ea 119 }
mbedalvaro 0:345b3bc7a0ea 120
mbedalvaro 0:345b3bc7a0ea 121 void Lockin::clearBuffer(){
mbedalvaro 0:345b3bc7a0ea 122 for(int i=0; i<BUFFER_SIZE; i++){
mbedalvaro 0:345b3bc7a0ea 123 buffer[i] = 0;
mbedalvaro 0:345b3bc7a0ea 124 }
mbedalvaro 0:345b3bc7a0ea 125 buffer_pos = BUFFER_SIZE;
mbedalvaro 0:345b3bc7a0ea 126 }
mbedalvaro 0:345b3bc7a0ea 127
mbedalvaro 0:345b3bc7a0ea 128 /*
mbedalvaro 0:345b3bc7a0ea 129 void Lockin::catchInterupt(uint32_t value){
mbedalvaro 0:345b3bc7a0ea 130 buffer_pos++;
mbedalvaro 0:345b3bc7a0ea 131 buffer_pos%=BUFFER_SIZE;
mbedalvaro 0:345b3bc7a0ea 132 buffer[buffer_pos] = value;
mbedalvaro 0:345b3bc7a0ea 133 }
mbedalvaro 0:345b3bc7a0ea 134 */
mbedalvaro 0:345b3bc7a0ea 135
mbedalvaro 0:345b3bc7a0ea 136 //****** aquisition method *****//
mbedalvaro 0:345b3bc7a0ea 137 float Lockin::getLastValue(){
mbedalvaro 0:345b3bc7a0ea 138 return buffer[buffer_pos];
mbedalvaro 0:345b3bc7a0ea 139 }
mbedalvaro 0:345b3bc7a0ea 140
mbedalvaro 0:345b3bc7a0ea 141 float Lockin::getSmoothValue(){
mbedalvaro 0:345b3bc7a0ea 142 float smoothValue = buffer[0];
mbedalvaro 0:345b3bc7a0ea 143 for(int i=1; i<BUFFER_SIZE; i++){
mbedalvaro 0:345b3bc7a0ea 144 smoothValue += buffer[i];
mbedalvaro 0:345b3bc7a0ea 145 }
mbedalvaro 0:345b3bc7a0ea 146 smoothValue /= BUFFER_SIZE;
mbedalvaro 0:345b3bc7a0ea 147
mbedalvaro 0:345b3bc7a0ea 148 return smoothValue;
mbedalvaro 0:345b3bc7a0ea 149 }
mbedalvaro 0:345b3bc7a0ea 150
mbedalvaro 0:345b3bc7a0ea 151 float Lockin::getMedianValue(){
mbedalvaro 0:345b3bc7a0ea 152 //this method applies a median filter to the buffer
mbedalvaro 0:345b3bc7a0ea 153 //It reduces the salt-and-pepper noise
mbedalvaro 0:345b3bc7a0ea 154 //It seems that this noise is very strong on certain mBed board, but not all...
mbedalvaro 0:345b3bc7a0ea 155
mbedalvaro 0:345b3bc7a0ea 156 float orderedBuffer[BUFFER_SIZE_MEDIAN];
mbedalvaro 0:345b3bc7a0ea 157
mbedalvaro 0:345b3bc7a0ea 158 //sort half of the buffer:
mbedalvaro 0:345b3bc7a0ea 159
mbedalvaro 0:345b3bc7a0ea 160 //copy buffer
mbedalvaro 0:345b3bc7a0ea 161 for(int i=0; i<BUFFER_SIZE_MEDIAN; i++){
mbedalvaro 0:345b3bc7a0ea 162 orderedBuffer[i] = buffer[(buffer_pos+BUFFER_SIZE-i+DELAY_BUFFER_MEDIAN)%BUFFER_SIZE];
mbedalvaro 0:345b3bc7a0ea 163 }
mbedalvaro 0:345b3bc7a0ea 164
mbedalvaro 0:345b3bc7a0ea 165 //order buffer
mbedalvaro 0:345b3bc7a0ea 166 for(int i=0; i<BUFFER_SIZE_MEDIAN-1; i++){
mbedalvaro 0:345b3bc7a0ea 167 int minPos = i;
mbedalvaro 0:345b3bc7a0ea 168
mbedalvaro 0:345b3bc7a0ea 169 //get min
mbedalvaro 0:345b3bc7a0ea 170 for(int j=i+1; j<BUFFER_SIZE_MEDIAN; j++){
mbedalvaro 0:345b3bc7a0ea 171 if(orderedBuffer[j] < orderedBuffer[minPos]) minPos = j;
mbedalvaro 0:345b3bc7a0ea 172 }
mbedalvaro 0:345b3bc7a0ea 173
mbedalvaro 0:345b3bc7a0ea 174 //swap min to the right position
mbedalvaro 0:345b3bc7a0ea 175 if(minPos != i){
mbedalvaro 0:345b3bc7a0ea 176 int tmpMin = orderedBuffer[minPos];
mbedalvaro 0:345b3bc7a0ea 177 orderedBuffer[minPos] = orderedBuffer[i];
mbedalvaro 0:345b3bc7a0ea 178 orderedBuffer[i] = tmpMin;
mbedalvaro 0:345b3bc7a0ea 179 }
mbedalvaro 0:345b3bc7a0ea 180 }
mbedalvaro 0:345b3bc7a0ea 181
mbedalvaro 0:345b3bc7a0ea 182 return orderedBuffer[BUFFER_SIZE_MEDIAN/2];
mbedalvaro 0:345b3bc7a0ea 183 }