Rework tone detector

- Send buffer pointers from ISR to userspace
- Use ADC interrupt to fetch data, not TIM6
- Increase size of buffer and do double-buffering
- Implement DTMF detectors
- Compare relative results instead of using absolute thresholds
- Add an IIR averaging filter on the results

1 files changed, 75 insertions, 43 deletions

diff --git a/src/glutt-o-logique/audio_in.c b/src/glutt-o-logique/audio_in.c
index 743c79b..a820b5f 100644
--- a/src/glutt-o-logique/audio_in.c
+++ b/src/glutt-o-logique/audio_in.c
@@ -26,61 +26,74 @@
 #include "stm32f4xx_gpio.h"
 #include "stm32f4xx_adc.h"
 
+#include "GPIO/usart.h"
 #include "Core/common.h"
 #include "Audio/audio_in.h"
 #include "queue.h"
 
 // APB1 prescaler = 4, see bsp/system_stm32f4xx.c
 #define APB1_FREQ (168000000ul / 4)
-#define ADC2_SAMPLE_FREQ 16000
-#define ADC2_CHANNEL_AUDIO ADC_Channel_14
+#define ADC2_CHANNEL_AUDIO ADC_Channel_9
 
 // see doc/pio.txt for allocation
 #define PINS_ADC2 /* PB1 on ADC2 IN9 */ (GPIO_Pin_1)
 
-#warning "TODO: initialise ADC2 and use it for NF input"
-
-// The TIM6 ISR reads from ADC2 and writes into this buffer
-static int16_t adc2_values[AUDIO_IN_BUF_LEN];
+// The TIM6 ISR reads from ADC2 and writes into these double buffers
+static int16_t adc2_values[2][AUDIO_IN_BUF_LEN];
+static int     adc2_current_buffer = 0; // which buffer is being written into
 static int     adc2_values_end = 0;
+static int32_t adc2_lost_samples = 0;
 
-// ADC2 data from interrupt to userspace goes through the queue
+// ADC2 data from interrupt to userspace. The queue contains the buffer index
 static QueueHandle_t adc2_values_queue;
 
 /* ISR for Timer6 and DAC1&2 underrun */
-void TIM6_DAC_IRQHandler(void)
+void TIM6_DAC_IRQHandler(void);
+
+void TIM6_DAC_IRQHandler()
 {
     if (TIM_GetITStatus(TIM6, TIM_IT_Update)) {
-        if (ADC_GetFlagStatus(ADC2, ADC_FLAG_EOC) == SET) {
-            uint16_t value = ADC_GetConversionValue(ADC2);
-            /* input range: 0 to 65535
-             * output range: -32768 to 32767 */
-            adc2_values[adc2_values_end++] = (int32_t)value - 32768;
-            if (adc2_values_end == AUDIO_IN_BUF_LEN) {
-                int success = xQueueSendToBackFromISR(
-                        adc2_values_queue,
-                        adc2_values,
-                        NULL);
-
-                adc2_values_end = 0;
-
-                if (success == pdFALSE) {
-                    trigger_fault(FAULT_SOURCE_ADC2);
-                }
-            }
-        }
-        else {
-#warning "handle fault"
-        }
-
         ADC_SoftwareStartConv(ADC2);
-
         TIM_ClearITPendingBit(TIM6, TIM_IT_Update);
     }
+    else {
+        usart_debug("%x\r\n", TIM6->SR);
+        trigger_fault(FAULT_SOURCE_TIM6_ISR);
+    }
+}
+
+void ADC_IRQHandler(void);
+void ADC_IRQHandler()
+{
+    if (ADC_GetFlagStatus(ADC2, ADC_FLAG_EOC) == SET) {
+        uint16_t value = ADC_GetConversionValue(ADC2);
+
+        ADC_ClearITPendingBit(ADC2, ADC_IT_EOC);
+
+        /* input range: 0 to 2^12
+         * output range: -32768 to 32767 */
+        adc2_values[adc2_current_buffer][adc2_values_end++] = (int32_t)value - (1 << 11);
+        if (adc2_values_end == AUDIO_IN_BUF_LEN) {
+            int success = xQueueSendToBackFromISR(
+                    adc2_values_queue,
+                    &adc2_current_buffer,
+                    NULL);
+
+            adc2_values_end = 0;
+            adc2_current_buffer = (adc2_current_buffer + 1) % 2;
+
+            if (success == pdFALSE) {
+                adc2_lost_samples += AUDIO_IN_BUF_LEN;
+            }
+        }
+    }
+    else {
+        adc2_lost_samples++;
+    }
 }
 
 // Timer6 is used for ADC2 sampling
-static void enable_timer6(void)
+static void enable_timer6()
 {
     /* TIM6 Periph clock enable */
     RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM6, ENABLE);
@@ -88,26 +101,27 @@ static void enable_timer6(void)
     /* Time base configuration */
     TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
     TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
-    TIM_TimeBaseStructure.TIM_Period = (int)(APB1_FREQ/ADC2_SAMPLE_FREQ);
-    TIM_TimeBaseStructure.TIM_Prescaler = 0;
-    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
+    TIM_TimeBaseStructure.TIM_Period = (int)(APB1_FREQ/AUDIO_IN_RATE);
+    TIM_TimeBaseStructure.TIM_Prescaler = 1;
+    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
     TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
     TIM_TimeBaseInit(TIM6, &TIM_TimeBaseStructure);
 
     NVIC_InitTypeDef NVIC_InitStructure;
     NVIC_InitStructure.NVIC_IRQChannel = TIM6_DAC_IRQn;
-    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
+    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 5;
     NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
     NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
     NVIC_Init(&NVIC_InitStructure);
+    NVIC_SetPriority(TIM6_DAC_IRQn, 5);
 
-    TIM_Cmd(TIM6, ENABLE);
-    ADC_SoftwareStartConv(ADC2);
     TIM_ITConfig(TIM6, TIM_IT_Update, ENABLE);
+    ADC_SoftwareStartConv(ADC2);
+    TIM_Cmd(TIM6, ENABLE);
 }
 
 
-void audio_in_initialize(int rate)
+void audio_in_initialize()
 {
     RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC2, ENABLE);
     RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
@@ -131,18 +145,36 @@ void audio_in_initialize(int rate)
     ADC_InitStruct.ADC_NbrOfConversion = 1;
     ADC_Init(ADC2, &ADC_InitStruct);
 
+    ADC_RegularChannelConfig(ADC2, ADC2_CHANNEL_AUDIO, /*rank*/ 1, ADC_SampleTime_15Cycles);
+    ADC_ClearITPendingBit(ADC2, ADC_IT_EOC);
+    ADC_ITConfig(ADC2, ADC_IT_EOC, ENABLE);
+
+    NVIC_InitTypeDef NVIC_InitStructure;
+    NVIC_InitStructure.NVIC_IRQChannel = ADC_IRQn;
+    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 7;
+    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
+    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
+    NVIC_Init(&NVIC_InitStructure);
+    NVIC_SetPriority(ADC_IRQn, 7);
+
     ADC_Cmd(ADC2, ENABLE);
 
-    adc2_values_queue = xQueueCreate(4, AUDIO_IN_BUF_LEN);
+
+    adc2_values_queue = xQueueCreate(4, sizeof(adc2_current_buffer));
     if (adc2_values_queue == 0) {
-        while(1); /* fatal error */
+        trigger_fault(FAULT_SOURCE_ADC2_QUEUE);
     }
 
     enable_timer6();
 }
 
-void audio_in_get_buffer(int16_t *buffer /*of length AUDIO_IN_BUF_LEN*/ )
+int32_t audio_in_get_buffer(int16_t **buffer /*of length AUDIO_IN_BUF_LEN*/ )
 {
-    while (!xQueueReceive(adc2_values_queue, buffer, portMAX_DELAY)) {}
+    int buf_ix = 0;
+    while (!xQueueReceive(adc2_values_queue, &buf_ix, portMAX_DELAY)) {}
+
+    *buffer = adc2_values[buf_ix];
+
+    return adc2_lost_samples;
 }