Repo re-org

1 files changed, 168 insertions, 0 deletions

diff --git a/reset-controller/fw/src/freq_meas.c b/reset-controller/fw/src/freq_meas.c
new file mode 100644
index 0000000..035ffd4
--- /dev/null
+++ b/reset-controller/fw/src/freq_meas.c
@@ -0,0 +1,168 @@
+
+#ifndef SIMULATION
+#include <stm32f407xx.h>
+#endif
+
+#include <unistd.h>
+#include <math.h>
+
+#include <arm_math.h>
+#include <levmarq.h>
+
+#include "freq_meas.h"
+#include "sr_global.h"
+#include "simulation.h"
+
+
+/* FTT window lookup table defined in generated/fmeas_fft_window.c */
+extern const float * const fmeas_fft_window_table;
+
+/* jury-rig some definitions for these functions since the ARM headers only export an over-generalized variable bin size
+ * variant. */
+extern arm_status arm_rfft_32_fast_init_f32(arm_rfft_fast_instance_f32 * S);
+extern arm_status arm_rfft_64_fast_init_f32(arm_rfft_fast_instance_f32 * S);
+extern arm_status arm_rfft_128_fast_init_f32(arm_rfft_fast_instance_f32 * S);
+extern arm_status arm_rfft_256_fast_init_f32(arm_rfft_fast_instance_f32 * S);
+extern arm_status arm_rfft_512_fast_init_f32(arm_rfft_fast_instance_f32 * S);
+extern arm_status arm_rfft_1024_fast_init_f32(arm_rfft_fast_instance_f32 * S);
+extern arm_status arm_rfft_2048_fast_init_f32(arm_rfft_fast_instance_f32 * S);
+extern arm_status arm_rfft_4096_fast_init_f32(arm_rfft_fast_instance_f32 * S);
+
+#define CONCAT(A, B, C) A ## B ## C
+#define arm_rfft_init_name(nbits) CONCAT(arm_rfft_, nbits, _fast_init_f32)
+
+void func_gauss_grad(float *out, float *params, int x, void *userdata);
+float func_gauss(float *params, int x, void *userdata);
+
+int adc_buf_measure_freq(uint16_t adc_buf[FMEAS_FFT_LEN], float *out) {
+    int rc;
+    float in_buf[FMEAS_FFT_LEN];
+    float out_buf[FMEAS_FFT_LEN];
+    /*
+    DEBUG_PRINTN("    [emulated adc buf] ");
+    for (size_t i=0; i<FMEAS_FFT_LEN; i++)
+        DEBUG_PRINTN("%5d, ", adc_buf[i]);
+    DEBUG_PRINTN("\n");
+    */
+    //DEBUG_PRINT("Applying window function");
+    for (size_t i=0; i<FMEAS_FFT_LEN; i++)
+        in_buf[i] = ((float)adc_buf[i] / (float)FMEAS_ADC_MAX - 0.5) * fmeas_fft_window_table[i];
+
+    //DEBUG_PRINT("Running FFT");
+    arm_rfft_fast_instance_f32 fft_inst;
+    if ((rc = arm_rfft_init_name(FMEAS_FFT_LEN)(&fft_inst)) != ARM_MATH_SUCCESS) {
+        *out = NAN;
+        return rc;
+    }
+
+    /*
+    DEBUG_PRINTN("    [input] ");
+    for (size_t i=0; i<FMEAS_FFT_LEN; i++)
+        DEBUG_PRINTN("%010f, ", in_buf[i]);
+    DEBUG_PRINTN("\n");
+    */
+#ifndef SIMULATION
+    GPIOA->BSRR = 1<<12;
+#endif
+    arm_rfft_fast_f32(&fft_inst, in_buf, out_buf, 0);
+#ifndef SIMULATION
+    GPIOA->BSRR = 1<<12<<16;
+#endif
+
+#define FMEAS_FFT_WINDOW_MIN_F_HZ 30.0f
+#define FMEAS_FFT_WINDOW_MAX_F_HZ 70.0f
+    const float binsize_hz = (float)FMEAS_ADC_SAMPLING_RATE / FMEAS_FFT_LEN;
+    const size_t first_bin = (int)(FMEAS_FFT_WINDOW_MIN_F_HZ / binsize_hz);
+    const size_t last_bin = (int)(FMEAS_FFT_WINDOW_MAX_F_HZ / binsize_hz + 0.5f);
+    const size_t nbins = last_bin - first_bin + 1;
+
+    /*
+    DEBUG_PRINT("binsize_hz=%f first_bin=%zd last_bin=%zd nbins=%zd", binsize_hz, first_bin, last_bin, nbins);
+    DEBUG_PRINTN("    [bins real] ");
+    for (size_t i=0; i<FMEAS_FFT_LEN/2; i+=2)
+        DEBUG_PRINTN("%010f, ", out_buf[i]);
+    DEBUG_PRINTN("\n    [bins imag] ");
+    for (size_t i=1; i<FMEAS_FFT_LEN/2; i+=2)
+        DEBUG_PRINTN("%010f, ", out_buf[i]);
+    DEBUG_PRINT("\n");
+
+    DEBUG_PRINT("Repacking FFT results");
+    */
+    /* Copy real values of target data to front of output buffer */
+    for (size_t i=0; i<nbins; i++) {
+        float real = out_buf[2 * (first_bin + i)];
+        float imag = out_buf[2 * (first_bin + i) + 1];
+        out_buf[i] = sqrtf(real*real + imag*imag);
+    }
+
+    /*
+    DEBUG_PRINT("Running Levenberg-Marquardt");
+    */
+    LMstat lmstat;
+    levmarq_init(&lmstat);
+
+    float a_max = 0.0f;
+    int i_max = 0;
+    for (size_t i=0; i<nbins; i++) {
+        if (out_buf[i] > a_max) {
+            a_max = out_buf[i];
+            i_max = i;
+        }
+    }
+
+    float par[3] = {
+        a_max, i_max, 1.0f
+    };
+    /*
+    DEBUG_PRINT("    par_pre={%010f, %010f, %010f}", par[0], par[1], par[2]);
+    */
+
+#ifndef SIMULATION
+    GPIOA->BSRR = 1<<12;
+#endif
+    if (levmarq(3, par, nbins, out_buf, NULL, func_gauss, func_gauss_grad, NULL, &lmstat) < 0) {
+#ifndef SIMULATION
+        GPIOA->BSRR = 1<<12<<16;
+#endif
+        *out = NAN;
+        return -1;
+    }
+#ifndef SIMULATION
+    GPIOA->BSRR = 1<<12<<16;
+#endif
+
+    /*
+    DEBUG_PRINT("    par_post={%010f, %010f, %010f}", par[0], par[1], par[2]);
+
+    DEBUG_PRINT("done.");
+    */
+    float res = (par[1] + first_bin) * binsize_hz;
+    if (par[1] < 2 || res < 5 || res > 150 || par[0] < 1) {
+        *out = NAN;
+        return -1;
+    }
+    
+    *out = res;
+    return 0;
+}
+
+float func_gauss(float *params, int x, void *userdata) {
+    UNUSED(userdata);
+    float a = params[0], b = params[1], c = params[2];
+    float n = x-b;
+    return a*expf(-n*n / (2.0f* c*c));
+}
+
+void func_gauss_grad(float *out, float *params, int x, void *userdata) {
+    UNUSED(userdata);
+    float a = params[0], b = params[1], c = params[2];
+    float n = x-b;
+    float e = expf(-n*n / (2.0f * c*c));
+    
+    /* d/da */
+    out[0] = e;
+    /* d/db */
+    out[1] = a*n/(c*c) * e;
+    /* d/dc */
+    out[2] = a*n*n/(c*c*c) * e;
+}