Test for microphone sampling using MCU

tests/platform/mic_test.c

@@ -0,0 +1,133 @@
+/***************************************************************************
+ *   Copyright (C) 2020 by Federico Amedeo Izzo IU2NUO,                    *
+ *                         Niccolò Izzo IU2KIN,                            *
+ *                         Frederik Saraci IU2NRO,                         *
+ *                         Silvano Seva IU2KWO                             *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 3 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, see <http://www.gnu.org/licenses/>   *
+ ***************************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <interfaces/delays.h>
+#include <interfaces/gpio.h>
+#include <hwconfig.h>
+
+static const char hexdigits[]="0123456789abcdef";
+void printUnsignedInt(unsigned int x)
+{
+    char result[]="....\r";
+    for(int i=3;i>=0;i--)
+    {
+        result[i]=hexdigits[x & 0xf];
+        x>>=4;
+    }
+    puts(result);
+}
+
+int main()
+{
+//     platform_init();
+
+    static const size_t numSamples = 45*1024;       // 80kB
+    uint16_t *sampleBuf = ((uint16_t *) malloc(numSamples * sizeof(uint16_t)));
+
+    gpio_setMode(GREEN_LED, OUTPUT);
+    gpio_setMode(RED_LED,   OUTPUT);
+    gpio_setMode(AIN_MIC,   INPUT_ANALOG);
+    gpio_setMode(MIC_PWR,   OUTPUT);
+    gpio_setPin(MIC_PWR);
+
+    delayMs(3000);
+
+    RCC->APB2ENR |= RCC_APB2ENR_ADC1EN;
+    RCC->APB1ENR |= RCC_APB1ENR_TIM2EN;
+    RCC->AHB1ENR |= RCC_AHB1ENR_DMA2EN;
+    __DSB();
+
+    /*
+     * TIM2 for conversion triggering via TIM2_TRGO, that is counter reload.
+     * AP1 frequency is 42MHz, configure for 8kHz interrupt rate.
+     */
+    TIM2->PSC = 41;     /* Tick rate 1MHz     */
+    TIM2->ARR = 124;    /* Overflow rate 8kHz */
+    TIM2->CNT = 0;
+    TIM2->EGR = TIM_EGR_UG;
+    TIM2->CR2 = TIM_CR2_MMS_1;
+    TIM2->CR1 = TIM_CR1_CEN;
+
+    /* DMA2 Stream 0 configuration:
+     * - channel 0: ADC1
+     * - low priority
+     * - half-word transfer, both memory and peripheral
+     * - increment memory
+     * - peripheral-to-memory transfer
+     * - no interrupts
+     */
+    DMA2_Stream0->PAR = ((uint32_t) &(ADC1->DR));
+    DMA2_Stream0->M0AR = ((uint32_t) sampleBuf);
+    DMA2_Stream0->NDTR = numSamples;
+    DMA2_Stream0->CR = DMA_SxCR_MSIZE_0     /* Memory size: 16 bit     */
+                     | DMA_SxCR_PSIZE_0     /* Peripheral size: 16 bit */
+                     | DMA_SxCR_PL_0        /* Medium priority         */
+                     | DMA_SxCR_MINC        /* Increment memory        */
+                     | DMA_SxCR_EN;
+
+    /*
+     * ADC clock is APB2 frequency divided by 8, giving 10.5MHz.
+     * A conversion takes 12 cycles.
+     */
+    ADC->CCR |= ADC_CCR_ADCPRE;
+    ADC1->SMPR2 = ADC_SMPR2_SMP0
+                | ADC_SMPR2_SMP1
+                | ADC_SMPR2_SMP3
+                | ADC_SMPR2_SMP8;
+
+    ADC1->SQR1 = 0;    /* One channel to be converted */
+    ADC1->SQR3 = 3;    /* CH3, vox level on PA3       */
+
+    /*
+     * No overrun interrupt, 12-bit resolution, no analog watchdog, no
+     * discontinuous mode, enable scan mode, no end of conversion interrupts,
+     * enable continuous conversion (free-running).
+     */
+    ADC1->CR1 |= ADC_CR1_DISCEN;
+    ADC1->CR2 |= ADC_CR2_EXTEN_0    /* Trigger on rising edge        */
+              |  ADC_CR2_EXTSEL_1
+              |  ADC_CR2_EXTSEL_2   /* 0b0110 TIM2_TRGO trig. source */
+              |  ADC_CR2_DDS        /* Enable DMA data transfer      */
+              |  ADC_CR2_DMA
+              |  ADC_CR2_ALIGN
+              |  ADC_CR2_ADON;      /* Enable ADC                    */
+
+    while((DMA2_Stream0->CR & DMA_SxCR_EN) == 1)
+    {
+        gpio_togglePin(GREEN_LED);
+        delayMs(250);
+    }
+
+    gpio_clearPin(GREEN_LED);
+    gpio_setPin(RED_LED);
+
+    delayMs(10000);
+
+    for(size_t i = 0; i < numSamples; i++)
+    {
+        printUnsignedInt(sampleBuf[i]);
+    }
+
+    while(1) ;
+
+    return 0;
+}