IOGS / LaserGame / Project
Dependencies: mbed nRF24L01P mbed-dsp
Diff: main.cpp
- Revision:
- 0:96c89b4dc711
- Child:
- 1:47d90ce030a3
- Child:
- 2:76fbb91a0331
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/main.cpp Tue Dec 08 12:10:01 2020 +0000 @@ -0,0 +1,66 @@ +#include "mbed.h" +#include "arm_math.h" +/* Include mbed-dsp libraries */ +#include "dsp.h" +#include "arm_common_tables.h" +#include "arm_const_structs.h" + +#define SAMPLES 512 /* 256 real party and 256 imaginary parts */ +#define FFT_SIZE SAMPLES / 2 /* FFT size is always the same size as we have samples, so 256 in our case */ + +float32_t Input[SAMPLES]; +float32_t Output[FFT_SIZE]; +bool trig=0; +int indice = 0; + +DigitalOut myled(LED1); +AnalogIn myADC(A0); +AnalogOut myDAC(A2); +Serial pc(USBTX, USBRX); +Ticker timer; + +void sample(){ + myled = 1; + if(indice < SAMPLES){ + Input[indice] = myADC.read() - 0.5f; //Real part NB removing DC offset + Input[indice + 1] = 0; //Imaginary Part set to zero + indice += 2; + } + else{ trig = 0; } + myled = 0; +} + +int main() { + float maxValue; // Max FFT value is stored here + uint32_t maxIndex; // Index in Output array where max value is + + while(1) { + if(trig == 0){ + timer.detach(); + // Init the Complex FFT module, intFlag = 0, doBitReverse = 1 + //NB using predefined arm_cfft_sR_f32_lenXXX, in this case XXX is 256 + arm_cfft_f32(&arm_cfft_sR_f32_len256, Input, 0, 1); + + // Complex Magniture Module put results into Output(Half size of the Input) + arm_cmplx_mag_f32(Input, Output, FFT_SIZE); + Output[0] = 0; + //Calculates maxValue and returns corresponding value + arm_max_f32(Output, FFT_SIZE/2, &maxValue, &maxIndex); + + myDAC=1.0; //SYNC Pulse to DAC Output + wait_us(20); //Used on Oscilliscope set trigger level to the highest + myDAC=0.0; //point on this pulse + + for(int i=0; i < FFT_SIZE / 2; i++){ + myDAC=(Output[i]) * 0.9; // Scale to Max Value and scale to 90 / 100 + wait_us(10); //Each pulse of 10us is 50KHz/256 = 195Hz resolution + } + myDAC=0.0; + pc.printf("MAX = %lf, %d \r\n", maxValue, maxIndex); + wait(0.2); + trig = 1; + indice = 0; + timer.attach_us(&sample,40); //20us 50KHz sampling rate + } + } +} \ No newline at end of file