Wrote hdc2021debr driver

Author: Deven-water

general/include/hdc2021debr.h

@@ -0,0 +1,61 @@
+#ifndef hdc2021debr_h
+#define hdc2021debr_h
+#include <stdbool.h>
+#include <stdint.h>
+/**
+ * https://www.ti.com/lit/ds/symlink/hdc2021.pdf
+ * --Datasheet
+ * 
+ */
+
+#define HDC2021_I2C_ADDR \
+	0x40 /* If ADDR is connected to VDD, 0x41  This is shifted left as it is required to be read as a dev address.*/
+
+typedef enum {
+    REG_TEMP_LOW = 0x00,
+    REG_TEMP_HIGH = 0x01,
+    REG_HUMID_LOW = 0x02,
+    REG_HUMID_HIGH = 0x03,
+	REG_STATUS = 0x04,
+	REG_DEVICE_CONFIG = 0x0E,
+    REG_MEASURE_CONFIG = 0x0F
+} HDC2021_REG_ADDR_t;
+
+/** Function Pointers */
+typedef int (*Write_ptr)(uint8_t *data, uint8_t dev_address, uint8_t length);
+typedef int (*Read_ptr)(uint8_t *data, uint8_t reg, uint8_t dev_address,
+			uint8_t length);
+
+typedef struct {
+	Write_ptr write_reg;
+	Read_ptr read_reg;
+	float temp;
+	float humidity;
+	bool is_heater_enabled;
+	uint8_t dev_address;
+} hdc2021debr_t;
+
+/**
+ * @brief Initializes an HDC2021 Driver
+ *
+ * @param hdc2021 - hdc2021debr driver
+ * @return int - Status code
+ */
+int hdc2021_init(hdc2021debr_t *hdc2021, Write_ptr write_reg, Read_ptr read_reg,
+		   uint8_t dev_address);
+/**
+ * @brief Toggles the status of the internal heater
+ *
+ * @param hdc2021 - hdc2021debr driver
+ * @param enable - true to enable, false to disable
+ * @return int - Status code
+ */
+int hdc2021_toggle_heater(hdc2021debr_t *hdc2021, bool enable);
+/**
+ * @brief Retrieves the temperature and humidity
+ * @note Call hdc2021_trigger_oneshot() and wait a couple ms before calling this
+ * @param hdc2021 - hdc2021debr driver
+ * @return int - Status code
+ */
+int hdc2021_get_temp_humid(hdc2021debr_t *hdc2021);
+#endif

general/src/hdc2021debr.c

@@ -0,0 +1,99 @@
+#include "hdc2021debr.h"
+#include <stdbool.h>
+#include <stdio.h>
+
+static int hdc2021_write_reg(hdc2021debr_t *hdc2021, uint8_t reg, uint8_t data) 
+{
+	uint8_t buffer[2] = {reg, data};
+	return hdc2021->write_reg(buffer, hdc2021->dev_address, sizeof(buffer));
+}
+
+static int hdc2021_read_reg(hdc2021debr_t *hdc2021, uint8_t reg, uint8_t *data,
+			  uint8_t length) 
+{
+    return hdc2021->read_reg(data, reg, hdc2021->dev_address, length);
+}
+
+int hdc2021_init(hdc2021debr_t *hdc2021, Write_ptr write_reg, Read_ptr read_reg,
+		    uint8_t dev_address)
+{
+	hdc2021->write_reg = write_reg;
+	hdc2021->read_reg = read_reg;
+	hdc2021->dev_address = dev_address << 1u;
+
+	return 0;
+}
+
+int hdc2021_toggle_heater(hdc2021debr_t *hdc2021, bool enable)
+{
+	uint8_t device_config;
+
+	if (hdc2021_read_reg(hdc2021, REG_DEVICE_CONFIG, &device_config,
+			  sizeof(device_config))) 
+	{
+		return 1;
+	};
+
+	// the 3rd bit toggles the heater
+	if (enable) {
+		device_config |= (1 << 3);
+	} else {
+		device_config &= ~(1 << 3);
+	};
+
+	if (hdc2021_write_reg(hdc2021, REG_DEVICE_CONFIG, device_config)) 
+	{
+		return 1;
+	};
+
+	return 0;
+
+}
+/**
+ * @brief triggers oneshot measurement
+ *
+ * @param hdc2021 - hdc2021debr driver
+ * @return int - Status code
+ */
+int hdc2021_trigger_oneshot(hdc2021debr_t *hdc2021)
+{
+    uint8_t config;
+
+    if (hdc2021_read_reg(hdc2021, REG_MEASURE_CONFIG, &config, 1)) {
+        return 1;
+    }
+
+    config |= 0x01;
+
+    if (hdc2021_write_reg(hdc2021, REG_MEASURE_CONFIG, config)) {
+        return 1;
+    }
+
+    return 0;
+}
+
+int hdc2021_get_temp_humid(hdc2021debr_t *hdc2021) 
+{
+	uint8_t buffer[4];
+
+	if (hdc2021_trigger_oneshot(hdc2021)) {
+		return 1;
+	}
+
+
+    if (hdc2021_read_reg(hdc2021, REG_TEMP_LOW, buffer, 4)) 
+    {
+        return 1;
+    };
+
+    uint16_t temp_bytes = (buffer[1] << 8) | buffer[0];
+    uint16_t humid_bytes = (buffer[3] << 8) | buffer[2];
+
+    float tempVal = (((float)temp_bytes/65536.0f) * 165.0f) - 40.0f;
+    hdc2021->temp = tempVal;
+
+    float humidVal = ((float)humid_bytes/65536.0f) * 100.0f;
+    hdc2021->humidity = humidVal;
+
+    return 0;
+}