Kevin Kadooka / Mbed 2 deprecated Nucleo_FDC1004

Sample code to interface with TI FDC1004 capacitance-to-digital-converter (CDC), multiplexed in a 8x8 grid array by TI SN74LVC1G3157 SPDT mux

Dependencies:   mbed-dsp mbed

main.cpp@0:7e77b4f4582c, 2017-08-02 (annotated)

Committer:
kkado
Date:
Wed Aug 02 22:11:11 2017 +0000
Revision:
0:7e77b4f4582c
Initial commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
kkado 0:7e77b4f4582c 1 //Test code to read from FDC1004
kkado 0:7e77b4f4582c 2 //Kevin Kadooka, April 2017
kkado 0:7e77b4f4582c 3
kkado 0:7e77b4f4582c 4 #include "mbed.h"
kkado 0:7e77b4f4582c 5 #include <ctype.h>
kkado 0:7e77b4f4582c 6 #include "arm_math.h"
kkado 0:7e77b4f4582c 7 #include "arm_const_structs.h"
kkado 0:7e77b4f4582c 8
kkado 0:7e77b4f4582c 9 #define SAMPLES 128 //# of continuous samples to read
kkado 0:7e77b4f4582c 10 #define DUMMIES 10 //# of dummy readings to make before actually recording data (sometimes first few readings are bunk)
kkado 0:7e77b4f4582c 11
kkado 0:7e77b4f4582c 12 DigitalOut col1(PA_1); //Define the pins used to switch rows & cols
kkado 0:7e77b4f4582c 13 DigitalOut col2(PH_1);
kkado 0:7e77b4f4582c 14 DigitalOut col3(PA_4);
kkado 0:7e77b4f4582c 15 DigitalOut col4(PB_0);
kkado 0:7e77b4f4582c 16 DigitalOut col5(PC_2);
kkado 0:7e77b4f4582c 17 DigitalOut col6(PC_1);
kkado 0:7e77b4f4582c 18 DigitalOut col7(PC_3);
kkado 0:7e77b4f4582c 19 DigitalOut col8(PC_0);
kkado 0:7e77b4f4582c 20
kkado 0:7e77b4f4582c 21 DigitalOut row1(PA_3);
kkado 0:7e77b4f4582c 22 DigitalOut row2(PA_2);
kkado 0:7e77b4f4582c 23 DigitalOut row3(PA_10);
kkado 0:7e77b4f4582c 24 DigitalOut row4(PC_4);
kkado 0:7e77b4f4582c 25 DigitalOut row5(PB_3);
kkado 0:7e77b4f4582c 26 DigitalOut row6(PB_5);
kkado 0:7e77b4f4582c 27 DigitalOut row7(PB_13);
kkado 0:7e77b4f4582c 28 DigitalOut row8(PB_4);
kkado 0:7e77b4f4582c 29
kkado 0:7e77b4f4582c 30 I2C i2c(PB_9, PB_8); //Initialize i2c master, where PB_9 is SDA, PB_8 is SCL
kkado 0:7e77b4f4582c 31 Serial pc(SERIAL_TX, SERIAL_RX); //Init serial connection to PC
kkado 0:7e77b4f4582c 32 Timer t; //Timing and stuff
kkado 0:7e77b4f4582c 33
kkado 0:7e77b4f4582c 34 const static arm_cfft_instance_f32 *S; //Floating point structure for FFT
kkado 0:7e77b4f4582c 35 const int addr = 0xA0; //This is the 8-bit address, 7-bit address is 0x50
kkado 0:7e77b4f4582c 36 float C[SAMPLES]; //Array to hold capacitance values
kkado 0:7e77b4f4582c 37 float FFTinput[SAMPLES*2]; //Array to hold FFT input, where [0] is first real value, [1] first imag value, etc...
kkado 0:7e77b4f4582c 38 float FFToutput[SAMPLES]; //Array to hold FFT output
kkado 0:7e77b4f4582c 39 uint32_t t_now; //Timing variable
kkado 0:7e77b4f4582c 40 uint16_t w; //Iter
kkado 0:7e77b4f4582c 41
kkado 0:7e77b4f4582c 42 ////////////////////////////////////////////////////////////////////////////////
kkado 0:7e77b4f4582c 43 // FUNCTIONS //
kkado 0:7e77b4f4582c 44 ////////////////////////////////////////////////////////////////////////////////
kkado 0:7e77b4f4582c 45
kkado 0:7e77b4f4582c 46 void capInit(){
kkado 0:7e77b4f4582c 47 char cmd[3]; //Configure the FDC1004
kkado 0:7e77b4f4582c 48 cmd[0] = 0x08; //Register
kkado 0:7e77b4f4582c 49 cmd[1] = 0b00010001; //MSB
kkado 0:7e77b4f4582c 50 cmd[2] = 0b00100000; //LSB
kkado 0:7e77b4f4582c 51 i2c.write(addr,cmd,3);
kkado 0:7e77b4f4582c 52 }
kkado 0:7e77b4f4582c 53
kkado 0:7e77b4f4582c 54 float capRead(){
kkado 0:7e77b4f4582c 55 int16_t lb1, lb2, lb3;
kkado 0:7e77b4f4582c 56 uint16_t lbb1, lbb2, lbb3;
kkado 0:7e77b4f4582c 57 char data[2];
kkado 0:7e77b4f4582c 58 float result;
kkado 0:7e77b4f4582c 59
kkado 0:7e77b4f4582c 60 char cmd[3]; //Start a single measurement on CIN1 with appropriate CAPDAC settings (bytes 9:5)
kkado 0:7e77b4f4582c 61 cmd[0] = 0x0C;
kkado 0:7e77b4f4582c 62 cmd[1] = 0b00000100;
kkado 0:7e77b4f4582c 63 cmd[2] = 0b10000000;
kkado 0:7e77b4f4582c 64 i2c.write(addr,cmd,3);
kkado 0:7e77b4f4582c 65
kkado 0:7e77b4f4582c 66 wait_ms(10); //Wait for measurement to complete. Alternatively we could read the status register, but this is reliable enough
kkado 0:7e77b4f4582c 67
kkado 0:7e77b4f4582c 68 i2c.start(); //Point to 0x00 and read MSB (2)
kkado 0:7e77b4f4582c 69 i2c.write(addr & 0xFE);
kkado 0:7e77b4f4582c 70 i2c.write(0x00);
kkado 0:7e77b4f4582c 71 i2c.stop();
kkado 0:7e77b4f4582c 72
kkado 0:7e77b4f4582c 73 i2c.read(addr,data,2);
kkado 0:7e77b4f4582c 74 lb1 = data[0];
kkado 0:7e77b4f4582c 75 lb2 = data[1];
kkado 0:7e77b4f4582c 76
kkado 0:7e77b4f4582c 77 i2c.start(); //Point to 0x01 and read LSB (1)
kkado 0:7e77b4f4582c 78 i2c.write(addr & 0xFE);
kkado 0:7e77b4f4582c 79 i2c.write(0x01);
kkado 0:7e77b4f4582c 80 i2c.stop();
kkado 0:7e77b4f4582c 81
kkado 0:7e77b4f4582c 82 i2c.start();
kkado 0:7e77b4f4582c 83 i2c.write(addr | 0x01);
kkado 0:7e77b4f4582c 84 lb3 = i2c.read(0);
kkado 0:7e77b4f4582c 85 i2c.stop();
kkado 0:7e77b4f4582c 86
kkado 0:7e77b4f4582c 87 lbb1 = lb1*256+lb2; //Reconstruct the 3 bytes into a 24-bit 2's complement value, divide by 2^19 to get cap value
kkado 0:7e77b4f4582c 88 lbb2 = lbb1 >> 11;
kkado 0:7e77b4f4582c 89 lbb3 = 0b0000011111111111 & lbb1;
kkado 0:7e77b4f4582c 90 result = lbb2 + (float)lbb3/2048 + (float)lb3/1048576;
kkado 0:7e77b4f4582c 91 //pc.printf("lb1 = %d, lb2 = %d, lb3 = %d\n",lb1,lb2,lb3);
kkado 0:7e77b4f4582c 92 //pc.printf("%f\n",result);
kkado 0:7e77b4f4582c 93
kkado 0:7e77b4f4582c 94 return result;
kkado 0:7e77b4f4582c 95 }
kkado 0:7e77b4f4582c 96
kkado 0:7e77b4f4582c 97 void printCap(){
kkado 0:7e77b4f4582c 98 for(uint16_t i = 0; i < SAMPLES; i++){
kkado 0:7e77b4f4582c 99 if(i == SAMPLES-1){
kkado 0:7e77b4f4582c 100 pc.printf("%f\n",C[i]);
kkado 0:7e77b4f4582c 101 }
kkado 0:7e77b4f4582c 102 else{
kkado 0:7e77b4f4582c 103 pc.printf("%f,",C[i]);
kkado 0:7e77b4f4582c 104 }
kkado 0:7e77b4f4582c 105 }
kkado 0:7e77b4f4582c 106 }
kkado 0:7e77b4f4582c 107
kkado 0:7e77b4f4582c 108 void printFFT(){
kkado 0:7e77b4f4582c 109 for(uint16_t i = 0; i < SAMPLES; i++){
kkado 0:7e77b4f4582c 110 if(i == SAMPLES-1){
kkado 0:7e77b4f4582c 111 pc.printf("%f\n",FFToutput[i]);
kkado 0:7e77b4f4582c 112 }
kkado 0:7e77b4f4582c 113 else{
kkado 0:7e77b4f4582c 114 pc.printf("%f,",FFToutput[i]);
kkado 0:7e77b4f4582c 115 }
kkado 0:7e77b4f4582c 116 }
kkado 0:7e77b4f4582c 117 }
kkado 0:7e77b4f4582c 118
kkado 0:7e77b4f4582c 119 void makeFFTinput(){
kkado 0:7e77b4f4582c 120 for(uint16_t i = 0; i < SAMPLES; i++){
kkado 0:7e77b4f4582c 121 FFTinput[2*i] = C[i];
kkado 0:7e77b4f4582c 122 FFTinput[2*i+1] = 0;
kkado 0:7e77b4f4582c 123 }
kkado 0:7e77b4f4582c 124 }
kkado 0:7e77b4f4582c 125
kkado 0:7e77b4f4582c 126 void removeOffset(){
kkado 0:7e77b4f4582c 127 float sum = 0;
kkado 0:7e77b4f4582c 128 for(uint16_t i = 0; i < SAMPLES; i++){
kkado 0:7e77b4f4582c 129 sum = sum + C[i];
kkado 0:7e77b4f4582c 130 }
kkado 0:7e77b4f4582c 131 float mean = sum/SAMPLES;
kkado 0:7e77b4f4582c 132 for(uint16_t i = 0; i < SAMPLES; i++){
kkado 0:7e77b4f4582c 133 C[i] = C[i] - mean;
kkado 0:7e77b4f4582c 134 }
kkado 0:7e77b4f4582c 135 }
kkado 0:7e77b4f4582c 136
kkado 0:7e77b4f4582c 137 void sensorSelect(uint8_t row, uint8_t col){ //Still need to sanitize inputs to only allow 1 <= row <= 8, 1 <= col <= 8
kkado 0:7e77b4f4582c 138 uint8_t rowbyte = 2^(row - 1); //For example, when row = 1, rowbyte = 1 = 0b00000001, row = 2, rowbyte = 2 = 0b00000010... etc
kkado 0:7e77b4f4582c 139 uint8_t colbyte = 2^(col - 1);
kkado 0:7e77b4f4582c 140
kkado 0:7e77b4f4582c 141 row1 = (rowbyte & 0b00000001); //Check value of bit 0, and write to pin
kkado 0:7e77b4f4582c 142 row2 = (rowbyte & 0b00000010)>>1; //Check value of bit 1, etc.
kkado 0:7e77b4f4582c 143 row3 = (rowbyte & 0b00000100)>>2;
kkado 0:7e77b4f4582c 144 row4 = (rowbyte & 0b00001000)>>3;
kkado 0:7e77b4f4582c 145 row5 = (rowbyte & 0b00010000)>>4;
kkado 0:7e77b4f4582c 146 row6 = (rowbyte & 0b00100000)>>5;
kkado 0:7e77b4f4582c 147 row7 = (rowbyte & 0b01000000)>>6;
kkado 0:7e77b4f4582c 148 row8 = (rowbyte & 0b10000000)>>7;
kkado 0:7e77b4f4582c 149
kkado 0:7e77b4f4582c 150 col1 = (colbyte & 0b00000001);
kkado 0:7e77b4f4582c 151 col2 = (colbyte & 0b00000010)>>1;
kkado 0:7e77b4f4582c 152 col3 = (colbyte & 0b00000100)>>2;
kkado 0:7e77b4f4582c 153 col4 = (colbyte & 0b00001000)>>3;
kkado 0:7e77b4f4582c 154 col5 = (colbyte & 0b00010000)>>4;
kkado 0:7e77b4f4582c 155 col6 = (colbyte & 0b00100000)>>5;
kkado 0:7e77b4f4582c 156 col7 = (colbyte & 0b01000000)>>6;
kkado 0:7e77b4f4582c 157 col8 = (colbyte & 0b10000000)>>7;
kkado 0:7e77b4f4582c 158 }
kkado 0:7e77b4f4582c 159
kkado 0:7e77b4f4582c 160 ////////////////////////////////////////////////////////////////////////////////
kkado 0:7e77b4f4582c 161 // MAIN //
kkado 0:7e77b4f4582c 162 ////////////////////////////////////////////////////////////////////////////////
kkado 0:7e77b4f4582c 163
kkado 0:7e77b4f4582c 164 int main(){
kkado 0:7e77b4f4582c 165 S = &arm_cfft_sR_f32_len128;
kkado 0:7e77b4f4582c 166 t.start();
kkado 0:7e77b4f4582c 167
kkado 0:7e77b4f4582c 168
kkado 0:7e77b4f4582c 169 col1 = 1;
kkado 0:7e77b4f4582c 170 col2 = 0;
kkado 0:7e77b4f4582c 171 col3 = 0;
kkado 0:7e77b4f4582c 172 col4 = 0;
kkado 0:7e77b4f4582c 173 col5 = 0;
kkado 0:7e77b4f4582c 174 col6 = 0;
kkado 0:7e77b4f4582c 175 col7 = 0;
kkado 0:7e77b4f4582c 176 col8 = 0;
kkado 0:7e77b4f4582c 177
kkado 0:7e77b4f4582c 178 row1 = 0;
kkado 0:7e77b4f4582c 179 row2 = 0;
kkado 0:7e77b4f4582c 180 row3 = 0;
kkado 0:7e77b4f4582c 181 row4 = 0;
kkado 0:7e77b4f4582c 182 row5 = 0;
kkado 0:7e77b4f4582c 183 row6 = 0;
kkado 0:7e77b4f4582c 184 row7 = 0;
kkado 0:7e77b4f4582c 185 row8 = 1;
kkado 0:7e77b4f4582c 186
kkado 0:7e77b4f4582c 187
kkado 0:7e77b4f4582c 188 //sensorSelect(1,1);
kkado 0:7e77b4f4582c 189
kkado 0:7e77b4f4582c 190 pc.baud(115200);
kkado 0:7e77b4f4582c 191 capInit();
kkado 0:7e77b4f4582c 192
kkado 0:7e77b4f4582c 193 while(1){
kkado 0:7e77b4f4582c 194 // for(uint8_t j = 1; j <= 8; j++){
kkado 0:7e77b4f4582c 195 // for(uint8_t i = 1; i <= 8; i++){
kkado 0:7e77b4f4582c 196 // sensorSelect(i,j);
kkado 0:7e77b4f4582c 197
kkado 0:7e77b4f4582c 198 w = 0;
kkado 0:7e77b4f4582c 199 t_now = t.read_us();
kkado 0:7e77b4f4582c 200 while(w < SAMPLES+DUMMIES){
kkado 0:7e77b4f4582c 201 if(t.read_us()-t_now >= 16666){
kkado 0:7e77b4f4582c 202 //t_now = t.read_us();
kkado 0:7e77b4f4582c 203 if(w < DUMMIES){
kkado 0:7e77b4f4582c 204 capRead();
kkado 0:7e77b4f4582c 205 //printf("dummy measurement %d",w);
kkado 0:7e77b4f4582c 206 }
kkado 0:7e77b4f4582c 207 else{
kkado 0:7e77b4f4582c 208 C[w-DUMMIES] = capRead();
kkado 0:7e77b4f4582c 209 //printf("t = %d, C = %f\n",t_now,C[w]);
kkado 0:7e77b4f4582c 210 }
kkado 0:7e77b4f4582c 211 w++;
kkado 0:7e77b4f4582c 212 }
kkado 0:7e77b4f4582c 213 }
kkado 0:7e77b4f4582c 214 //removeOffset();
kkado 0:7e77b4f4582c 215 printCap();
kkado 0:7e77b4f4582c 216 //pc.printf("Making FFT input...\n");
kkado 0:7e77b4f4582c 217 //makeFFTinput();
kkado 0:7e77b4f4582c 218 //pc.printf("Calculating FFT...\n");
kkado 0:7e77b4f4582c 219 //arm_cfft_f32(S,FFTinput,0,1);
kkado 0:7e77b4f4582c 220 //pc.printf("Calculating FFT mag...\n");
kkado 0:7e77b4f4582c 221 //arm_cmplx_mag_f32(FFTinput,FFToutput,SAMPLES);
kkado 0:7e77b4f4582c 222 //printFFT();
kkado 0:7e77b4f4582c 223 // }
kkado 0:7e77b4f4582c 224 // }
kkado 0:7e77b4f4582c 225 }
kkado 0:7e77b4f4582c 226 }