Updated Readme with example

twi_test.c

@@ -0,0 +1,128 @@
+/*
+ * TWI_Test.c
+ *
+ * Created: 08-Jun-19 10:06:47 AM
+ * Author : TEP SOVICHEA
+ */ 
+
+#include "uart.h"
+#include "twi_master.h"
+#include <avr/io.h>
+#include <util/delay.h>
+
+/************************************************************************/
+/*							Initializations                             */
+/************************************************************************/
+
+#define MPU6050_ADDR	0x68
+
+/* MPU6050 register address */
+#define ACCEL_XOUT_H	0x3B
+#define ACCEL_XOUT_L	0x3C
+#define ACCEL_YOUT_H	0x3D
+#define ACCEL_YOUT_L	0x3E
+#define ACCEL_ZOUT_H	0x3F
+#define ACCEL_ZOUT_L	0x40
+#define PWR_MGMT_1		0x6B
+
+typedef struct 
+{
+	float x;
+	float y;
+	float z;
+} mpu_data_t;
+
+
+/************************************************************************/
+/*							Prototype functions                         */
+/************************************************************************/
+
+void ERROR_CHECK(ret_code_t error_code);
+void mpu_init(void);
+void mpu_get_accel_raw(mpu_data_t* mpu_data);
+void mpu_get_accel(mpu_data_t* mpu_data);
+
+	
+/************************************************************************/
+/*							Function definitions                        */
+/************************************************************************/
+
+void ERROR_CHECK(ret_code_t error_code)
+{
+	if (error_code != SUCCESS)
+	{
+		/* Print error code and loop indefinitely until reset */
+		printf(BR "App error! error_code = 0x%02X\n" RESET, error_code);
+		while (1); // loop indefinitely
+	}
+}
+
+
+void mpu_init(void)
+{
+	ret_code_t error_code;
+	puts("Write 0 to PWR_MGMT_1 reg to wakeup MPU.");
+	uint8_t data[2] = {PWR_MGMT_1, 0};
+	error_code = tw_master_transmit(MPU6050_ADDR, data, sizeof(data), false);
+	ERROR_CHECK(error_code);
+}
+
+
+void mpu_get_accel_raw(mpu_data_t* mpu_data)
+{
+	ret_code_t error_code;
+	/* 2 registers for each of accel x, y and z data */
+	uint8_t data[6];
+	
+	data[0] = ACCEL_XOUT_H;
+	error_code = tw_master_transmit(MPU6050_ADDR, data, 1, true);
+	ERROR_CHECK(error_code);
+	
+	error_code = tw_master_receive(MPU6050_ADDR, data, sizeof(data));
+	ERROR_CHECK(error_code);
+	
+	/* Default accel config +/- 2g */
+	mpu_data->x = (int16_t)(data[0] << 8 | data[1]) / 16384.0;
+	mpu_data->y = (int16_t)(data[2] << 8 | data[3]) / 16384.0;
+	mpu_data->z = (int16_t)(data[4] << 8 | data[5]) / 16384.0;
+}
+
+
+void mpu_get_accel(mpu_data_t* mpu_data)
+{
+	mpu_get_accel_raw(mpu_data);
+	mpu_data->x = mpu_data->x * 9.81;
+	mpu_data->y = mpu_data->y * 9.81;
+	mpu_data->z = mpu_data->z * 9.81;
+}
+
+
+/************************************************************************/
+/*							Main application                            */
+/************************************************************************/
+
+int main(void)
+{
+    /* Initialize UART */
+    uart_init(250000); // bps
+    cli_reset();
+    puts(BY "Initializing TWI_Test Project...\n" RESET);
+    
+    /* Initialize project configuration */
+	tw_init(TW_FREQ_400K, true); // set I2C Frequency, enable internal pull-up
+	mpu_init();
+	mpu_data_t accel;
+    
+    puts(BG CURSOR_RIGHT("14") 
+        "--------------- Application Started ---------------\n" RESET);
+    
+	while (1)
+    {		
+		puts("Read accelerometer data.");
+		mpu_get_accel(&accel);
+		printf("Accel X: %5.2f\n", accel.x);
+		printf("Accel Y: %5.2f\n", accel.y);
+		printf("Accel Z: %5.2f\n", accel.z);
+		_delay_ms(200);
+	}
+}