analogue windspeed

include/rte_wx.h

@@ -20,6 +20,8 @@ extern float rte_wx_temperature_min_dallas_valid, rte_wx_temperature_max_dallas_
 extern float rte_wx_temperature_ms, rte_wx_temperature_ms_valid;
 extern float rte_wx_pressure, rte_wx_pressure_valid;
 
+extern uint16_t rte_wx_windspeed_pulses;
+
 extern uint8_t rte_wx_tx20_excessive_slew_rate;
 
 extern dht22Values rte_wx_dht, rte_wx_dht_valid;

src/it_handlers.c

@@ -121,6 +121,7 @@ void TIM1_TRG_COM_TIM17_IRQHandler(void) {
 
 void DMA1_Channel7_IRQHandler() {
 	NVIC_ClearPendingIRQ(DMA1_Channel7_IRQn);
+	DMA_ClearITPendingBit(DMA1_IT_GL7);
 
 	analog_anemometer_dma_irq();
 

src/rte_wx.c

@@ -15,6 +15,8 @@ float rte_wx_temperature_min_dallas_valid = 0.0f, rte_wx_temperature_max_dallas_
 float rte_wx_temperature_ms = 0.0f, rte_wx_temperature_ms_valid = 0.0f;
 float rte_wx_pressure = 0.0f, rte_wx_pressure_valid = 0.0f;
 
+uint16_t rte_wx_windspeed_pulses = 0;
+
 uint8_t rte_wx_tx20_excessive_slew_rate = 0;
 
 dht22Values rte_wx_dht, rte_wx_dht_valid;		// quality factor inside this structure

system/src/drivers/analog_anemometer.c

@@ -8,17 +8,37 @@
 #include "drivers/analog_anemometer.h"
 
 #include <stdint.h>
+#include <string.h>
 #include <stm32f10x_tim.h>
 #include <stm32f10x_dma.h>
 #include "drivers/gpio_conf.h"
+#include "rte_wx.h"
 
+#define MINUM_PULSE_LN 15
+#define MAXIMUM_PULSE_SLEW_RATE 4000
+
+// an array where DMA will store values of the timer latched by compare-capture input
 uint16_t analog_anemometer_windspeed_pulses_time[ANALOG_ANEMOMETER_SPEED_PULSES_N];
 
+uint16_t analog_anemometer_pulses_durations[ANALOG_ANEMOMETER_SPEED_PULSES_N];
+
+// a static copy of impulse-meters/second contact
+uint16_t analog_anemometer_pulses_per_ms_constant = 0;
+
+uint8_t analog_anemometer_timer_has_been_fired = 0;
+
+DMA_InitTypeDef DMA_InitStruct;
+
 void analog_anemometer_init(uint16_t pulses_per_ms, uint16_t mvolts_for_1deg,
 		uint16_t mvolts_for_359deg, uint8_t reversed) {
 
 	TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;
-	DMA_InitTypeDef DMA_InitStruct;
+
+	analog_anemometer_pulses_per_ms_constant = pulses_per_ms;
+
+	// initializing arrays;
+	memset(analog_anemometer_windspeed_pulses_time, 0x00, ANALOG_ANEMOMETER_SPEED_PULSES_N);
+	memset(analog_anemometer_pulses_durations, 0x00, ANALOG_ANEMOMETER_SPEED_PULSES_N);
 
 	// enabling the clock for TIM17
 	RCC->APB2ENR |= RCC_APB2ENR_TIM17EN;
@@ -63,10 +83,10 @@ void analog_anemometer_init(uint16_t pulses_per_ms, uint16_t mvolts_for_1deg,
 	DMA_InitStruct.DMA_BufferSize = ANALOG_ANEMOMETER_SPEED_PULSES_N;
 	DMA_InitStruct.DMA_DIR = DMA_DIR_PeripheralSRC;
 	DMA_InitStruct.DMA_M2M = DMA_M2M_Disable;
-	DMA_InitStruct.DMA_MemoryBaseAddr = analog_anemometer_windspeed_pulses_time;
+	DMA_InitStruct.DMA_MemoryBaseAddr = (uint32_t)analog_anemometer_windspeed_pulses_time;
 	DMA_InitStruct.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
 	DMA_InitStruct.DMA_MemoryInc = DMA_MemoryInc_Enable;
-	DMA_InitStruct.DMA_PeripheralBaseAddr = &TIM17->CCR1;
+	DMA_InitStruct.DMA_PeripheralBaseAddr = (uint32_t)&TIM17->CCR1;
 	DMA_InitStruct.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
 	DMA_InitStruct.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
 
@@ -81,9 +101,100 @@ void analog_anemometer_init(uint16_t pulses_per_ms, uint16_t mvolts_for_1deg,
 }
 
 void analog_anemometer_timer_irq(void) {
-
+	analog_anemometer_timer_has_been_fired = 1;
 }
 
 void analog_anemometer_dma_irq(void) {
-	DMA_ClearITPendingBit(DMA1_IT_GL7);
+	int i = 0;
+	uint16_t pulse_ln = 0;
+	uint16_t previous_pulse_ln = 0;
+	uint16_t minimum_pulse_ln = 60000;
+	uint16_t maximum_pulse_ln = 0;
+
+	// checking if timer overflowed (raised an iterrupt)
+	if (analog_anemometer_timer_has_been_fired == 1) {
+		rte_wx_windspeed_pulses = 1;
+
+		// reseting array to default values
+		for (i = 0; i < ANALOG_ANEMOMETER_SPEED_PULSES_N; i++)
+			analog_anemometer_windspeed_pulses_time[i] = 0;
+
+		DMA_Init(DMA1_Channel7, &DMA_InitStruct);
+		DMA1_Channel7->CCR |= DMA_CCR7_EN;
+		DMA1_Channel7->CCR |= DMA_CCR7_TCIE;
+
+		return;
+	}
+
+	// calculating pulses duration time
+	for (i = 0; i < ANALOG_ANEMOMETER_SPEED_PULSES_N - 1; i++) {
+		pulse_ln = analog_anemometer_windspeed_pulses_time[i + 1] -
+				analog_anemometer_windspeed_pulses_time[i];
+
+		analog_anemometer_pulses_durations[i] = pulse_ln;
+	}
+
+	// debouncing captured times
+	for (i = 0; i < ANALOG_ANEMOMETER_SPEED_PULSES_N; i++) {
+		if (analog_anemometer_pulses_durations[i] < MINUM_PULSE_LN)
+			analog_anemometer_pulses_durations[i] = 0;
+	}
+
+	// limiting slew rate
+	for (i = 1; i < ANALOG_ANEMOMETER_SPEED_PULSES_N; i++) {
+		previous_pulse_ln = analog_anemometer_pulses_durations[i - 1];
+		pulse_ln = analog_anemometer_pulses_durations[i];
+
+		// skipping pulses erased by debouncing
+		if (pulse_ln == 0 || previous_pulse_ln == 0) {
+			continue;
+		}
+
+		int32_t diff = pulse_ln - previous_pulse_ln;
+
+		// if current pulse is much longer than previous
+		if ( diff > MAXIMUM_PULSE_SLEW_RATE ) {
+			analog_anemometer_pulses_durations[i] = previous_pulse_ln + MAXIMUM_PULSE_SLEW_RATE;
+		}
+		// if previous pulse is much longer than current
+		else {
+			analog_anemometer_pulses_durations[i - 1] = pulse_ln + MAXIMUM_PULSE_SLEW_RATE;
+		}
+	}
+
+	// find maximum and minimum values within pulses duration
+	for (i = 0; i < ANALOG_ANEMOMETER_SPEED_PULSES_N; i++) {
+
+		pulse_ln = analog_anemometer_pulses_durations[i];
+
+		// skipping pulses erased by debouncing
+		if (pulse_ln == 0)
+			continue;
+
+		// find maximum and minimum values within pulses duration
+		if (pulse_ln < minimum_pulse_ln)
+			minimum_pulse_ln = pulse_ln;
+
+		if (pulse_ln > maximum_pulse_ln)
+			maximum_pulse_ln = pulse_ln;
+
+	}
+
+	// calculating the target pulse duration
+	rte_wx_windspeed_pulses = (uint16_t)((maximum_pulse_ln + minimum_pulse_ln) / 2);
+
+	// resetting the timer
+	analog_anemometer_timer_has_been_fired = 0;
+
+	for (i = 0; i < ANALOG_ANEMOMETER_SPEED_PULSES_N; i++)
+		analog_anemometer_windspeed_pulses_time[i] = 0;
+
+	for (i = 0; i < ANALOG_ANEMOMETER_SPEED_PULSES_N; i++)
+		analog_anemometer_pulses_durations[i] = 0;
+
+	DMA_Init(DMA1_Channel7, &DMA_InitStruct);
+	DMA1_Channel7->CCR |= DMA_CCR7_EN;
+	DMA1_Channel7->CCR |= DMA_CCR7_TCIE;
+
+	return;
 }