[DHT11] add working driver

Core/Inc/DHT11.h

@@ -0,0 +1,18 @@
+#ifndef __DHT11
+#define __DHT11
+
+#define SKIP_LOW while (!(GPIOD->IDR & 0x0800)) {}
+#define SKIP_HIGH while (GPIOD->IDR & 0x0800) {}
+
+__attribute__((packed))
+struct DHT11_Data {
+	uint8_t humid_integral;
+	uint8_t humid_decimal;
+	uint8_t temp_integral;
+	uint8_t temp_decimal;
+	uint8_t crc;
+};
+
+int DHT11_run_test(void);
+
+#endif

Core/Src/DHT11.c

@@ -0,0 +1,113 @@
+#include "main.h"
+#include "generic_macros.h"
+#include "lcd.h"
+#include "DHT11.h"
+
+extern TIM_HandleTypeDef htim2;
+
+static inline void wait(uint32_t wait_us)
+{
+	uint32_t target_time = TIM2->CNT;
+	target_time += wait_us << 4;
+
+	while (TIM2->CNT < target_time) {}
+}
+
+static inline size_t dht11_measure_high_duration(void)
+{
+	SKIP_LOW;
+	uint32_t start_time = TIM2->CNT;
+	SKIP_HIGH;
+	uint32_t end_time = TIM2->CNT;
+
+	// elapsed_time > 49us ? 1 : 0
+	return (end_time - start_time) > (49 << 4);
+}
+
+static size_t dht11_read_value(struct DHT11_Data *data)
+{
+	// treat data as a normal array to simplify read loop
+	uint8_t *buffer = (uint8_t *) data;
+
+	register uint32_t read_register = 0;
+
+	TIM2->CNT = 0;
+	HAL_TIM_Base_Start(&htim2);
+
+	GPIOD->MODER |= 0x00400000;       // enable output mode on GPIOD 11
+
+	GPIOD->BSRR = GPIO_PIN_11;        // enable DHT11
+	wait(50000);                      // hold HIGH for 50 ms
+	GPIOD->BSRR = GPIO_PIN_11 << 16;  // start signal
+	wait(30000);                      // hold it for 30 ms
+	GPIOD->BSRR = GPIO_PIN_11;        // pull up, DHT will now take control over the connection
+
+	wait(100);
+	GPIOD->MODER &= 0xFF3FFFFF;       // switch GPIOD 11 to input mode
+
+	// reading pull down from DHT11
+	SKIP_LOW;
+
+	// waiting for 500ms max
+	for (size_t i = TIM2->CNT + (500000 << 4); TIM2->CNT <= i; )
+		if (!(GPIOD->IDR & 0x0800))
+			goto reading_data;
+
+	// if didn't exit through goto, then DHT11 awaiting has timed out
+	return 1;
+
+reading_data:
+	// read 5 bytes of data
+	for (size_t i = 0; i < 5; i++) {
+		for (register size_t j = 0; j < 8; j++) {
+			read_register <<= 1;
+			read_register |= dht11_measure_high_duration();
+		}
+
+		buffer[i] = (uint8_t) read_register;
+	}
+
+	HAL_TIM_Base_Stop(&htim2);
+
+	return 0;
+}
+
+int DHT11_run_test(void)
+{
+	DISPLAY_CLEAR;
+	display_write_data_seq("DHT11 Temp+Humid");
+
+	struct DHT11_Data data;
+	size_t result = dht11_read_value(&data);
+
+	size_t checksum_mismatch = ((
+			data.humid_decimal
+			+ data.humid_integral
+			+ data.temp_decimal
+			+ data.temp_integral
+			) & 0xFF) != data.crc;
+
+	if (result) {
+		DISPLAY_SET_CURSOR(1, 4);
+		display_write_data_seq("StartTimeout");
+	} else if (checksum_mismatch) {
+		DISPLAY_SET_CURSOR(1, 4);
+		display_write_data_seq("CRC Fault");
+	} else {
+		DISPLAY_SET_CURSOR(1, 4);
+		display_write_data_seq("OK");
+
+		DISPLAY_SET_CURSOR(1, 7);
+		display_write_data_byte('0' + (data.humid_integral/10)%10);
+		display_write_data_byte('0' + (data.humid_integral)%10);
+		display_write_data_seq("% ");
+
+		display_write_data_byte('0' + (data.temp_integral/10)%10);
+		display_write_data_byte('0' + (data.temp_integral)%10);
+		display_write_data_byte('.');
+		display_write_data_byte('0' + data.temp_decimal);
+		display_write_data_seq("C");
+	}
+
+	return (result || checksum_mismatch);
+}

Core/Src/main.c

@@ -32,6 +32,7 @@
 #include "LIS302DL.h"
 #include "MP45DT02.h"
 #include "LSM9DS1.h"
+#include "DHT11.h"
 
 /* USER CODE END Includes */
 
@@ -75,10 +76,10 @@ SPI_HandleTypeDef hspi1;
 
 TIM_HandleTypeDef htim2;
 
-extern size_t display_current_frame;
-
 /* USER CODE BEGIN PV */
 
+extern size_t display_current_frame;
+
 static const int ((*executors[])(void)) = {
 		DNI_show_celsius,
 		PCA9685_run_test,
@@ -88,7 +89,8 @@ static const int ((*executors[])(void)) = {
 		LIS302DL_run_test,
 		MP45DT02_run_test,
 		LSM9DS1_test_accel,
-		LSM9DS1_test_magnet
+		LSM9DS1_test_magnet,
+		DHT11_run_test
 };
 
 static const void ((*cleanup_functions[])(void)) = {
@@ -100,6 +102,7 @@ static const void ((*cleanup_functions[])(void)) = {
 		NULL,
 		NULL,
 		LSM9DS1_cleanup_accel,
+		NULL,
 		NULL
 };
 
@@ -568,10 +571,17 @@ static void MX_GPIO_Init(void)
   GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
   HAL_GPIO_Init(GPIOE, &GPIO_InitStruct);
 
-  /*Configure GPIO pins : PD11 PD12 PD13 PD14
+  /*Configure GPIO pin : PD11 */
-                           PD15 PD4 PD7 */
+  GPIO_InitStruct.Pin = GPIO_PIN_11;
-  GPIO_InitStruct.Pin = GPIO_PIN_11|GPIO_PIN_12|GPIO_PIN_13|GPIO_PIN_14
+  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
-                          |GPIO_PIN_15|GPIO_PIN_4|GPIO_PIN_7;
+  GPIO_InitStruct.Pull = GPIO_NOPULL;
+  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
+  HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);
+
+  /*Configure GPIO pins : PD12 PD13 PD14 PD15
+                           PD4 PD7 */
+  GPIO_InitStruct.Pin = GPIO_PIN_12|GPIO_PIN_13|GPIO_PIN_14|GPIO_PIN_15
+                          |GPIO_PIN_4|GPIO_PIN_7;
   GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
   GPIO_InitStruct.Pull = GPIO_NOPULL;
   GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;

test1.ioc

@@ -121,6 +121,8 @@ PC8.Locked=true
 PC8.Signal=GPIO_Input
 PC9.Locked=true
 PC9.Signal=GPIO_Input
+PD11.GPIOParameters=GPIO_Speed
+PD11.GPIO_Speed=GPIO_SPEED_FREQ_VERY_HIGH
 PD11.Locked=true
 PD11.Signal=GPIO_Output
 PD12.Locked=true