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-rw-r--r--software/i2c_demo/i2c_demo.c318
1 files changed, 318 insertions, 0 deletions
diff --git a/software/i2c_demo/i2c_demo.c b/software/i2c_demo/i2c_demo.c
new file mode 100644
index 0000000..4011c09
--- /dev/null
+++ b/software/i2c_demo/i2c_demo.c
@@ -0,0 +1,318 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "platform.h"
+#include <string.h>
+#include <unistd.h>
+#include <math.h>
+#include "stdatomic.h"
+
+#define MPU6050_ADDR 0x68
+
+#define MPU6050_RA_ACCEL_XOUT_H 0x3B
+#define MPU6050_RA_ACCEL_XOUT_L 0x3C
+#define MPU6050_RA_ACCEL_YOUT_H 0x3D
+#define MPU6050_RA_ACCEL_YOUT_L 0x3E
+#define MPU6050_RA_ACCEL_ZOUT_H 0x3F
+#define MPU6050_RA_ACCEL_ZOUT_L 0x40
+#define MPU6050_RA_TEMP_OUT_H 0x41
+#define MPU6050_RA_TEMP_OUT_L 0x42
+#define MPU6050_RA_GYRO_XOUT_H 0x43
+#define MPU6050_RA_GYRO_XOUT_L 0x44
+#define MPU6050_RA_GYRO_YOUT_H 0x45
+#define MPU6050_RA_GYRO_YOUT_L 0x46
+#define MPU6050_RA_GYRO_ZOUT_H 0x47
+#define MPU6050_RA_GYRO_ZOUT_L 0x48
+#define MPU6050_RA_PWR_MGMT_1 0x6B
+#define MPU6050_RA_WHO_AM_I 0x75
+
+#define SDA PIN_8_OFFSET
+#define SCL PIN_9_OFFSET
+
+#define LONG 25 // Equals ~400KHz
+#define SHORT 5
+
+//busy wait for the specified time
+void wait_ms(uint64_t ms) {
+ static const uint64_t ms_tick = RTC_FREQ/1000;
+ volatile uint64_t * mtime = (uint64_t*) (CLINT_CTRL_ADDR + CLINT_MTIME);
+ uint64_t then = (ms_tick * ms) + *mtime;
+ while(*mtime<then);
+}
+
+inline void delay_number_of_nop(uint32_t count)
+{
+ for(volatile uint32_t j = 0; j < count; j++)
+ {
+ asm("nop");
+ }
+}
+
+_Bool i2c_busy(void)
+{
+ GPIO_REG(GPIO_INPUT_EN) |= ((0x1 << SCL) | (0x1 << SDA));
+ GPIO_REG(GPIO_OUTPUT_EN) &= ~((0x1 << SCL) | (0x1 << SDA));
+ return (GPIO_REG(GPIO_INPUT_VAL) & ((0x1 << SCL) | (0x1 << SDA))) != ((0x1 << SCL) | (0x1 << SDA));
+}
+
+void i2c_start(void)
+{
+ GPIO_REG(GPIO_INPUT_EN) &= ~((0x1 << SDA) | (0x1 << SCL));
+
+ GPIO_REG(GPIO_OUTPUT_VAL) &= ~(0x1 << SDA);
+ GPIO_REG(GPIO_OUTPUT_EN) |= (0x1 << SDA);
+ delay_number_of_nop(SHORT);
+ GPIO_REG(GPIO_OUTPUT_VAL) &= ~(0x1 << SCL);
+ GPIO_REG(GPIO_OUTPUT_EN) |= (0x1 << SCL);
+}
+
+void i2c_repeated_start(void)
+{
+ delay_number_of_nop(SHORT);
+ GPIO_REG(GPIO_OUTPUT_VAL) |= (0x1 << SCL);
+ GPIO_REG(GPIO_OUTPUT_EN) |= (0x1 << SCL);
+ delay_number_of_nop(SHORT);
+ i2c_start();
+}
+
+
+void i2c_stop(void)
+{
+ GPIO_REG(GPIO_INPUT_EN) |= (0x1 << SCL);
+ GPIO_REG(GPIO_OUTPUT_EN) &= ~(0x1 << SCL);
+ delay_number_of_nop(SHORT);
+ GPIO_REG(GPIO_INPUT_EN) |= (0x1 << SDA);
+ GPIO_REG(GPIO_OUTPUT_EN) &= ~(0x1 << SDA);
+}
+
+void i2c_init(void)
+{
+ //GPIO_REG(GPIO_IOF_EN) &= ((0x1 << SCL) | (0x1 << SDA));
+ GPIO_REG(GPIO_OUTPUT_EN) &= ~((0x1 << SCL) | (0x1 << SDA));
+ GPIO_REG(GPIO_PULLUP_EN) |= ((0x1 << SDA) | (0x1 << SCL));
+ GPIO_REG(GPIO_INPUT_EN) |= (0x1 << SDA) | (0x1 << SCL);
+}
+
+void i2c_send_bytes_rs(uint8_t* data, uint8_t size, _Bool rs, uint8_t* data_r, uint8_t size_r)
+{
+ uint8_t address_r = data[0] | 0x01;
+
+ for(uint8_t ii=0; ii<size; ii++)
+ {
+ GPIO_REG(GPIO_INPUT_EN) &= ~(0x1 << SDA);
+ GPIO_REG(GPIO_OUTPUT_EN) |= (0x1 << SDA);
+ for(uint8_t i=0; i<9; i++)
+ {
+ delay_number_of_nop(SHORT);
+
+ if(i != 8)
+ {
+ if(data[ii] & 0x80)
+ GPIO_REG(GPIO_OUTPUT_VAL) |= (0x1 << SDA);
+ else
+ GPIO_REG(GPIO_OUTPUT_VAL) &= ~(0x1 << SDA);
+ }
+ else
+ {
+ GPIO_REG(GPIO_INPUT_EN) |= (0x1 << SDA);
+ GPIO_REG(GPIO_OUTPUT_EN) &= ~(0x1 << SDA);
+ if((GPIO_REG(GPIO_INPUT_VAL) & (0x1 << SDA)) != 0x0)
+ {
+ printf("NO ACK\n");
+ }
+
+ GPIO_REG(GPIO_INPUT_EN) &= ~(0x1 << SDA);
+ GPIO_REG(GPIO_OUTPUT_EN) |= (0x1 << SDA);
+ if(rs == 0)
+ {
+ GPIO_REG(GPIO_OUTPUT_VAL) &= ~(0x1 << SDA);
+ }
+ else
+ {
+ GPIO_REG(GPIO_OUTPUT_VAL) |= (0x1 << SDA);
+ }
+
+ }
+ delay_number_of_nop(LONG-SHORT);
+
+ GPIO_REG(GPIO_OUTPUT_VAL) |= (0x1 << SCL);
+
+ delay_number_of_nop(LONG);
+
+ GPIO_REG(GPIO_OUTPUT_VAL) &= ~(0x1 << SCL);
+
+ data[ii] <<= 1;
+ }
+ }
+
+ if(rs == 0)
+ return;
+
+ GPIO_REG(GPIO_OUTPUT_VAL) |= (0x1 << SCL);
+
+ delay_number_of_nop(SHORT);
+
+ GPIO_REG(GPIO_OUTPUT_VAL) &= ~(0x1 << SDA);
+
+ delay_number_of_nop(SHORT);
+
+ GPIO_REG(GPIO_OUTPUT_VAL) &= ~(0x1 << SCL);
+
+ for(uint8_t i=0; i<9; i++)
+ {
+ delay_number_of_nop(SHORT);
+ if(i != 8)
+ {
+ if(address_r & 0x80)
+ GPIO_REG(GPIO_OUTPUT_VAL) |= (0x1 << SDA);
+ else
+ GPIO_REG(GPIO_OUTPUT_VAL) &= ~(0x1 << SDA);
+ }
+ else
+ {
+ GPIO_REG(GPIO_INPUT_EN) |= (0x1 << SDA);
+ GPIO_REG(GPIO_OUTPUT_EN) &= ~(0x1 << SDA);
+ if((GPIO_REG(GPIO_INPUT_VAL) & (0x1 << SDA)) != 0x0)
+ {
+ printf("NO ACK\n");
+ }
+ }
+ delay_number_of_nop(LONG-SHORT);
+
+ GPIO_REG(GPIO_OUTPUT_VAL) |= (0x1 << SCL);
+
+ delay_number_of_nop(LONG);
+
+ GPIO_REG(GPIO_OUTPUT_VAL) &= ~(0x1 << SCL);
+
+ address_r <<= 1;
+ }
+
+ // Receive Data
+ for(uint8_t ii=0; ii<size_r; ii++)
+ {
+ for(uint8_t i=0; i<9; i++)
+ {
+ GPIO_REG(GPIO_OUTPUT_VAL) |= (0x1 << SCL);
+
+ if(i!=8)
+ data_r[ii] <<= 1;
+
+ delay_number_of_nop(SHORT);
+
+ if(i!=8)
+ {
+ if((GPIO_REG(GPIO_INPUT_VAL) & (0x1 << SDA)) != 0x0)
+ {
+ data_r[ii] |= 0x1;
+ }
+ }
+ else if(ii == (size_r-1))
+ {
+ GPIO_REG(GPIO_INPUT_EN) &= ~(0x1 << SDA);
+ GPIO_REG(GPIO_OUTPUT_EN) |= (0x1 << SDA);
+ GPIO_REG(GPIO_OUTPUT_VAL) &= ~(0x1 << SDA);
+ } else {
+
+ }
+
+ delay_number_of_nop(LONG-SHORT);
+
+ GPIO_REG(GPIO_OUTPUT_VAL) &= ~(0x1 << SCL);
+
+ if((i==7) && (ii != (size_r-1))){
+ GPIO_REG(GPIO_INPUT_EN) &= ~(0x1 << SDA);
+ GPIO_REG(GPIO_OUTPUT_EN) |= (0x1 << SDA);
+ GPIO_REG(GPIO_OUTPUT_VAL) &= ~(0x1 << SDA);
+ }
+ delay_number_of_nop(LONG);
+
+ }
+
+ if(ii != (size_r-1)){
+ GPIO_REG(GPIO_INPUT_EN) |= (0x1 << SDA);
+ GPIO_REG(GPIO_OUTPUT_EN) &= ~(0x1 << SDA);
+ delay_number_of_nop(SHORT);
+ }
+ }
+}
+
+void write_byte(uint8_t address, uint8_t reg_addr, uint8_t val)
+{
+ uint8_t temp[3];
+ uint8_t data;
+ temp[0]=address<<1;
+ temp[1]=reg_addr;
+ temp[2]=val;
+ while(i2c_busy());
+ i2c_start();
+ i2c_send_bytes_rs(temp, sizeof(temp), 0, &data, 1);
+ i2c_stop();
+}
+
+uint8_t read_byte(uint8_t address, uint8_t reg_addr)
+{
+ uint8_t temp[2];
+ uint8_t data;
+ temp[0]=address<<1;
+ temp[1]=reg_addr;
+ while(i2c_busy());
+ i2c_start();
+ i2c_send_bytes_rs(temp, sizeof(temp), 1, &data, 1);
+ i2c_stop();
+ return data;
+}
+
+void read_bytes(uint8_t address, uint8_t reg_addr, uint8_t* data, uint8_t size)
+{
+ uint8_t temp[2];
+ temp[0]=address<<1;
+ temp[1]=reg_addr;
+ while(i2c_busy());
+ i2c_start();
+ i2c_send_bytes_rs(temp, sizeof(temp), 1, data, size);
+ i2c_stop();
+}
+
+int main(int argc, char **argv)
+{
+ uint8_t data;
+ uint8_t accel[6];
+
+ printf("BIT-BANG I2C DEMO with MPU-6050 IMU\n");
+
+ i2c_init();
+
+ printf("Power Management 1: 0x%02X\n", read_byte(MPU6050_ADDR, MPU6050_RA_PWR_MGMT_1));
+ write_byte(MPU6050_ADDR, MPU6050_RA_PWR_MGMT_1, 0x80);
+
+ wait_ms(10);
+
+ printf("Power Management 1: 0x%02X\n", read_byte(MPU6050_ADDR, MPU6050_RA_PWR_MGMT_1));
+ write_byte(MPU6050_ADDR, MPU6050_RA_PWR_MGMT_1, 0x00);
+
+ printf("CHIP_ID: 0x%02X\n", read_byte(MPU6050_ADDR, MPU6050_RA_WHO_AM_I));
+ printf("DONE\n");
+
+ while(1)
+ {
+ //for(uint8_t i=0; i<6; i++){
+ // accel[i]=read_byte(MPU6050_ADDR, 0x3B+i);
+ //}
+ read_bytes(MPU6050_ADDR, 0x3B, accel, 6);
+ int16_t x_accel = (accel[0]<<8)+accel[1];
+ int16_t y_accel = (accel[2]<<8)+accel[3];
+ int16_t z_accel = (accel[4]<<8)+accel[5];
+
+ float z_g = z_accel;
+ z_g = z_g/16384.0;
+ int32_t z_g_int = z_g*100;
+ z_g_int = abs(z_g_int);
+ printf("Gravity in Z %d.%d\n", z_g_int/100, z_g_int%100);
+
+ //printf("X: %06d, Y: %06d, Z: %06d\n", x_accel, y_accel, z_accel);
+
+ wait_ms(100);
+ }
+
+ return 0;
+}
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