(First draft) Added functions for reading/writing registers and conve…

…rting to real current, power, and voltage

general/include/INA226.h

@@ -0,0 +1,38 @@
+/*
+        INA226AQDGSRQ1 Current Sensor I2C Driver
+        Datasheet:
+        https://www.ti.com/lit/ds/symlink/ina226-q1.pdf
+*/
+
+#ifndef INA226_H
+#define INA226_H
+
+// REGISTERS
+#define INA226_CONFIGURATION 0x00
+#define INA226_SHUNT_VOLTAGE 0x01
+#define INA226_BUS_VOLTAGE   0x02
+#define INA226_POWER	     0x03
+#define INA226_CURRENT	     0x04
+#define INA226_CALIBRATION   0x05
+#define INA226_MASK_ENABLE   0x06
+#define INA226_ALERT_LIMIT   0x07
+#define INA226_MANUFACTURER  0xFE
+#define INA226_DIE_ID	     0xFF
+
+// CONFIGURATION MASKS
+#define INA226_CONFIG_RESET_MASK   0x8000 // Bit 15
+#define INA226_CONFIG_AVERAGE_MASK 0x0E00 // Bits 9-11
+#define INA226_CONFIG_BUSVC_MASK   0x01C0 // Bits 6-8
+#define INA226_CONFIG_SHUNTVC_MASK 0x0038 // Bits 3-5
+#define INA226_CONFIG_MODE_MASK	   0x0007 // Bits 0-2
+
+// Function Pointers
+typedef int (*WritePtr)(uint16_t dev_addr, uint8_t reg, uint16_t *data);
+typedef int (*ReadPtr)(uint16_t dev_addr, uint8_t reg, uint16_t *data);
+
+typedef struct {
+	uint16_t dev_addr;
+	WritePtr write;
+	ReadPtr read;
+	float current_lsb;
+} ina226_t;

general/src/INA226.c

@@ -0,0 +1,155 @@
+/*
+        INA226AQDGSRQ1 Current Sensor I2C Driver
+        Datasheet:
+        https://www.ti.com/lit/ds/symlink/ina226-q1.pdf
+*/
+
+#include "INA226.h"
+
+void ina226_init(ina226_t *ina, WritePtr write, ReadPtr read, uint16_t dev_addr)
+{
+	ina->write = write;
+	ina->read = read;
+	ina->dev_addr = dev_addr << 1u; // pretty sure it needs to be shifted
+	ina->current_lsb =
+		0; // temporary value before ina226_calibrate (not sure if i need this?)
+}
+
+int ina226_read_reg(ina226_t *ina, uint8_t reg, uint16_t *data)
+{
+	return ina->read(ina->dev_addr, reg, data);
+}
+
+int ina226_write_reg(ina226_t *ina, uint8_t reg, uint16_t *data)
+{
+	return ina->write(ina->dev_addr, reg, data);
+}
+
+// Writes calibration register. r_shunt in ohms, max_current in amps
+int ina226_calibrate(ina226_t *ina, float r_shunt, float max_current)
+{
+	float current_lsb = max_current / 32768;
+	float cal = 0.00512 / (current_lsb * r_shunt);
+	uint16_t cal_reg = (uint16_t)floorf(cal);
+	ina->current_lsb =
+		0.00512 /
+		(cal_reg *
+		 r_shunt); // need to store as an int but not sure how since different current_lsb values might need different scaling factors
+
+	return ina226_write_reg(ina, INA226_CALIBRATION, &cal_reg);
+}
+
+// Reads current in amps
+int ina226_read_current(ina226_t *ina, float *data)
+{
+	uint16_t current_reg;
+
+	int status = ina226_read_reg(ina, INA226_CURRENT, &current_reg);
+	if (status != 0) {
+		return status;
+	}
+
+	*data = (float)(int16_t)current_reg * ina->current_lsb;
+
+	return status;
+}
+
+// Reads power in watts
+int ina226_read_power(ina226_t *ina, float *data)
+{
+	uint16_t power_reg;
+
+	int status = ina226_read_reg(ina, INA226_POWER, &power_reg);
+	if (status != 0) {
+		return status;
+	}
+
+	*data = (float)(int16_t)power_reg * (ina->current_lsb * 25);
+
+	return status;
+}
+
+// Reads shunt voltage in volts
+int ina226_read_shunt_voltage(ina226_t *ina, float *data)
+{
+	uint16_t shunt_voltage_reg;
+
+	int status =
+		ina226_read_reg(ina, INA226_SHUNT_VOLTAGE, &shunt_voltage_reg);
+	if (status != 0) {
+		return status;
+	}
+
+	*data = (float)(int16_t)shunt_voltage_reg *
+		2.5e-6; // LSB = 2.5 uV per bit
+
+	return status;
+}
+
+// Reads bus voltage in volts
+int ina226_read_bus_voltage(ina226_t *ina, float *data)
+{
+	uint16_t bus_voltage_reg;
+
+	int status = ina226_read_reg(ina, INA226_BUS_VOLTAGE, &bus_voltage_reg);
+	if (status != 0) {
+		return status;
+	}
+
+	*data = (float)bus_voltage_reg * 1.25e-3; // LSB = 1.25 mV per bit
+
+	return status;
+}
+
+// Sets configuration register bits 0-11 (operating mode, shunt voltage conversion time, bus voltage conversion time, and averaging mode)
+// See datasheet for settings
+int ina226_configure(ina226_t *ina, uint8_t mode, uint8_t vshct, uint8_t vbusct,
+		     uint8_t avg)
+{
+	// (probably need to check if params <= 7 but im not sure)
+	uint16_t configuration;
+	configuration = (avg << 9) | (vbusct << 6) | (vshct << 3) | mode;
+	return ina226_write_reg(ina, INA226_CONFIGURATION, &configuration);
+}
+
+// Resets all registers to default values
+int ina226_reset(ina226_t ina)
+{
+	uint16_t reset = INA226_CONFIG_RESET_MASK;
+	return ina226_write_reg(ina, INA226_CONFIGURATION, &reset);
+}
+
+// Reads manufacturer id register (kinda pointless)
+int ina226_read_manufacturer_id(ina226_t ina, uint16_t *data)
+{
+	uint16_t manufacturer_id;
+
+	int status =
+		ina226_read_reg(ina, INA226_MANUFACTURER, &manufacturer_id);
+	if (status != 0) {
+		return status;
+	}
+
+	*data = manufacturer_id;
+
+	return status;
+}
+
+// Reads die id (also kinda pointless)
+int ina226_read_die_id(ina226_t ina, uint16_t *data)
+{
+	uint16_t die_id;
+
+	int status = ina226_read_reg(ina, INA226_DIE_ID, &die_id);
+	if (status != 0) {
+		return status;
+	}
+
+	*data = die_id;
+
+	return status;
+}
+
+// still need to do stuff w/ alert register and mask/enable register
+// might also want to have functions to set each individual setting in the configuration register
+// also not sure if the converted current, power, and voltage should be given as float