Weird problem with Intel Edison and IMU MPU-9150

[Frederic Philips]

Hi guys,

So I am trying to get measurements from the MPU-9150 sensor from Invensense using the Intel Edison. I am able to communicate with the sensor and the values seem sensible.

But after a specific number of cycles, I measure only a zero from all data registers. This error is repeatable: When I try to read the Accelerometer and Gyro data(6 data registers), the data stream stops exactly at 84 cycles. If I try to read jus the Accelerometer values, it stops at double the no. of cycles i.e. 168. I sense some data is overflowing, but couldn't figure out yet.

Looking for your reply and Thanks!

Cheers,

Frederic

Code:

MPU9150.h

1. //Self Test registers R/W
2. #define SELF_TEST_X 0x0D
3. #define SELF_TEST_Y 0x0E
4. #define SELF_TEST_Z 0x0F
5. #define SELF_TEST_A 0x0A
6. //Configuration Registers
7. #define SMPRT_DIV 0x19 //Sample Rate Divider
8. #define CONFIG 0x1A //FSYNC & DLPF config
9. #define GYRO_CONFIG 0x1B //Self-Test & Scale select
10. #define ACCEL_CONFIG 0x1C //Self-Test & Scale select
11. //Interrupt Registers
12. #define INT_ENABLE 0x38
13. #define INT_STATUS 0x3A
14. //Accelerometer Measurement Registers
15. #define ACCEL_XOUT_H 0x3B
16. #define ACCEL_XOUT_L 0x3C
17. #define ACCEL_YOUT_H 0x3D
18. #define ACCEL_YOUT_L 0x3E
19. #define ACCEL_ZOUT_H 0x3F
20. #define ACCEL_ZOUT_L 0x40
21. //Temperature Measurement Registers
22. //Temperature in degrees C = (TEMP_OUT Register Value as a signed quantity)/340 + 35
23. #define TEMP_OUT_H 0x41
24. #define TEMP_OUT_L 0x42
25. //Gyroscope Measurement Registers
26. #define GYRO_XOUT_H 0x43
27. #define GYRO_XOUT_L 0x44
28. #define GYRO_YOUT_H 0x45
29. #define GYRO_YOUT_L 0x46
30. #define GYRO_ZOUT_H 0x47
31. #define GYRO_ZOUT_L 0x48
32. //Power Management Registers
33. #define PWR_MGMT_1 0x6B
34. #define PWR_MGMT_2 0x6C
35. //Device i.d. Register
36. #define WHO_AM_I 0x75
37. /*
38. R1 - 0x69
39. R2 - 0x68
40. */
41. #define MPU_ADDR 0x68
42. //Reset the Registers and Power
43. #define PWR_RESET 0x80
44. #define DEVICE_ON 0x00
45. //Accelerometer Scale
46. #define ACCEL_2G 0x00
47. #define ACCEL_4G 0x08
48. #define ACCEL_8G 0x10
49. #define ACCEL_16G 0x18
50. //Gyroscope Scale
51. #define GYRO_250 0x00
52. #define GYRO_500 0x08
53. #define GYRO_1000 0x10
54. #define GYRO_2000 0x18
55. #define SAMPLE_RATE 0x00
56. #define DLPF_CFG 0x01

MPU9150.c

1. #include <stdio.h>
2. #include <stdlib.h>
3. #include <signal.h>
4. #include "mraa.h"
5. #include "MPU9150.h"
6. void MPU9150_I2C_Init(void);
7. void MPU9150_I2C_Config(void);
8. void MPU9150_I2C_Write(uint8_t address, uint8_t value);
9. void MPU9150_I2C_Read(uint8_t address, uint8_t *value);
10. int16_t MPU9150_Get_Measurement(uint8_t addrL, uint8_t addrH);
11. void sig_handler(int signum);
12. sig_atomic_tvolatile isrunning = 1;
13. //Acceleometer Measurement Storage Variables
14. int16_t Accel_X = 0;
15. int16_t Accel_Y = 0;
16. int16_t Accel_Z = 0;
17. //Gyroscope Measurement Storage Variables
18. int16_t Gyro_X = 0;
19. int16_t Gyro_Y = 0;
20. int16_t Gyro_Z = 0;
21. //Temperature Measurement Storage Variable
22. float Temperature = 0;
23. //Variable to Store LOW and HIGH Register values
24. uint8_t Measurement_L = 0;
25. uint8_t Measurement_H = 0;
26. int main(int argc, char **argv)
27. {
28. printf("--------------------------------------------------\n");
29. printf("------------------eGlove Project------------------\n");
30. printf("--------------------------------------------------\n");
31. sleep(1); //1s delay
32. signal(SIGINT, &sig_handler);
33. usleep(1000); //1ms delay
34. MPU9150_I2C_Init();
35. sleep(1); //1s delay
36. MPU9150_I2C_Config();
37. sleep(1); //1s delay
38. while(isrunning)
39. {
40. //Get Accelerometer Measurements
41. Accel_X = MPU9150_Get_Measurement(ACCEL_XOUT_L, ACCEL_XOUT_H);
42. Accel_Y = MPU9150_Get_Measurement(ACCEL_YOUT_L, ACCEL_YOUT_H);
43. Accel_Z = MPU9150_Get_Measurement(ACCEL_ZOUT_L, ACCEL_ZOUT_H);
44. //Get Gyroscope Measurements
45. Gyro_X = MPU9150_Get_Measurement(GYRO_XOUT_L, GYRO_XOUT_H);
46. Gyro_Y = MPU9150_Get_Measurement(GYRO_YOUT_L, GYRO_YOUT_H);
47. Gyro_Z = MPU9150_Get_Measurement(GYRO_ZOUT_L, GYRO_ZOUT_H);
48. //Print Accelerometer Values
49. printf("Accelerometer:\n X:%d\n Y:%d\n Z:%d\n ", Accel_X, Accel_Y, Accel_Z);
50. //Print Gyroscope Values
51. printf("Gyroscope:\n X:%d\n Y:%d\n Z:%d\n ", Gyro_X, Gyro_Y,Gyro_Z);
52. //Sample Readings every second
53. sleep(1); //1s delay
54. }
55. return MRAA_SUCCESS;
56. }
57. void MPU9150_I2C_Init(void)
58. {
59. mraa_init();
60. mraa_i2c_context mpu9150_i2c;
61. mpu9150_i2c = mraa_i2c_init(1);
62. if (mpu9150_i2c == NULL)
63. {
64. printf("MPU9150 I2C initialization failed, exit...\n");
65. exit(1);
66. }
67. printf("MPU9150 I2C initialized successfully\n");
68. mraa_i2c_address(mpu9150_i2c, MPU_ADDR);
69. printf("MPU9150 I2C Address set to 0x%x\n", MPU_ADDR);
70. }
71. void MPU9150_I2C_Config(void)
72. {
73. mraa_i2c_context mpu9150_i2c;
74. mpu9150_i2c = mraa_i2c_init(1);
75. //Reset all the Registers
76. mraa_i2c_address(mpu9150_i2c, MPU_ADDR);
77. MPU9150_I2C_Write(PWR_MGMT_1, PWR_RESET);
78. printf("MPU9150 Reset\n");
79. sleep(1); //1s delay
80. mraa_i2c_address(mpu9150_i2c, MPU_ADDR);
81. MPU9150_I2C_Write(PWR_MGMT_1, DEVICE_ON);
82. printf("MPU9150 Switched ON\n");
83. sleep(1); //1s delay
84. mraa_i2c_address(mpu9150_i2c, MPU_ADDR);
85. uint8_t data = mraa_i2c_read_byte_data(mpu9150_i2c, WHO_AM_I);
86. printf("Who am I: 0x%x\n", data);
87. sleep(1); //1s delay
88. MPU9150_I2C_Write(SMPRT_DIV, SAMPLE_RATE);
89. MPU9150_I2C_Write(CONFIG, DLPF_CFG);
90. //Set the Gyroscope Scale to 250°/s
91. MPU9150_I2C_Write(GYRO_CONFIG, GYRO_500);
92. //Set the Accelerometer Scale to 2G
93. MPU9150_I2C_Write(ACCEL_CONFIG, ACCEL_2G);
94. printf("Initialization Complete: All Systems are GO!!!\n");
95. }
96. void MPU9150_I2C_Write(uint8_t address, uint8_t value)
97. {
98. mraa_i2c_context mpu9150_i2c;
99. mpu9150_i2c = mraa_i2c_init(1);
100. //Set MPU Device Address
101. mraa_i2c_address(mpu9150_i2c, MPU_ADDR);
102. //Write Command and Data
103. mraa_i2c_write_byte_data(mpu9150_i2c, value, address);
104. }
105. void MPU9150_I2C_Read(uint8_t address, uint8_t *value)
106. {
107. mraa_i2c_context mpu9150_i2c;
108. mpu9150_i2c = mraa_i2c_init(1);
109. //Set ALS Device Address
110. mraa_i2c_address(mpu9150_i2c, MPU_ADDR);
111. //Write Command and Read Data
112. *value = mraa_i2c_read_byte_data(mpu9150_i2c, address);
113. }
114. int16_t MPU9150_Get_Measurement(uint8_t addrL, uint8_t addrH)
115. {
116. //Read & Store the Lower Byte
117. MPU9150_I2C_Read(addrL, &Measurement_L);
118. //Read & Store the Higher Byte
119. MPU9150_I2C_Read(addrH, &Measurement_H);
120. return (int16_t)((Measurement_H << 8) + Measurement_L);
121. }
122. //Signal Handler
123. void sig_handler(int signum)
124. {
125. if(signum == SIGINT)
126. {
127. isrunning = 0;
128. }
129. }

Console Screenshot:





Reference:

MPU-9150 Product Specification: http://43zrtwysvxb2gf29r5o0athu.wpengine.netdna-cdn.com/wp-content/uploads/2015/02/MPU-9150-Datasheet.pdf

MPU-9150 Register Map: http://43zrtwysvxb2gf29r5o0athu.wpe...ent/uploads/2015/02/MPU-9150-Register-Map.pdf