IPC Module - Gyroscope Service

This page contains documentation of the gyroscope part of IMU API.

According to the interface description, the values in the a_ipc_msg_gyro_publish_ind comes as an array of bytes. To be able to read out the actual values, these bytes need to be re-composed to an gyro_sample struct.

struct gyro_sample {
      int16_t x;
      int16_t y;
      int16_t z;
      int16_t pad;
      int64_t ts;
   } __attribute__ ((__packed__));

Gyroscope sample units: - x, y and z are reported in 1000x rad/s - Equivalent unit: mrad/s (milli-radians per second)

Here is an example of how to do this:

static void handle_publish_ind(a_ipc_msg* message)
{
   struct gyro_sample {
      int16_t x;
      int16_t y;
      int16_t z;
      int16_t pad;
      int64_t ts;
   } __attribute__ ((__packed__));

   struct gyro_sample* samples = (struct gyro_sample*)
      message->gyro_publish_ind.sample_buffer.value;

   int number_of_samples =
      message->gyro_publish_ind.sample_buffer.length /
      sizeof(struct gyro_sample);

   for (int i = 0; i < number_of_samples; i++)
   {
      printf("Received values (sample %d of %d):\n", i + 1, number_of_samples);
      printf("x: %i\n", samples[i].x);
      printf("y: %i\n", samples[i].y);
      printf("z: %i\n", samples[i].z);
      printf("time stamp: %lu\n", samples[i].ts);
   }

   exit_main_loop_with_return_code(0);
}

Messages

message gyro_data_profile_req

Parameters:: profile (enum gyro_data_profile) – Data profile to set
Return message:: gyro_data_profile_rsp

Request to set gyro data profile.

message gyro_data_profile_rsp

Parameters:

result (enum gyro_result) – Result of the operation
profile (enum gyro_data_profile) – Current data profile

Response to gyro data profile request.

message gyro_request_req

Parameters:: user (string) – User identifier, max 15 characters long.
Return message:: gyro_request_rsp

Request the gyro service.

message gyro_request_rsp

Parameters:: result (enum gyro_result) – Result of the operation

Gyro request result.

message gyro_release_req_norsp

Parameters:: user (string) – User identifier, max 15 characters long.

Release gyro service for given user user.

message gyro_configure_req

Parameters:

samplerate_sps (uint32) – Requested sample rate in samples per second
samples_per_buffer (uint32) – Number of samples per buffer

Return message:

gyro_configure_rsp

Request to configure the gyro service.

The supported values for samplerate and samples per buffer is board dependent and documented at IMU.

message gyro_configure_rsp

Parameters:

actual_samplerate_sps (uint32) – Actual sample rate configured, in samples per second
result (enum gyro_result) – Result of the operation

Sent in response to gyro_configure_req message.

message gyro_subscribe_req: Subscribe to gyro_publish_ind messages

message gyro_subscribe_rsp

Parameters:: result (enum ipc_subscribe_result)

Result from gyro_subscribe_req

message gyro_unsubscribe_req_norsp: Unsubscribe from gyro_publish_ind messages

message gyro_publish_ind

Parameters:

no_of_samples (uint32) – Number of samples included in sample buffer
sample_buffer (uint8[]) – The sample values. x/y/z values are in 1000x rad/s (mrad/s).

Gyro data event.

Enums

enum gyro_result

Result codes.

Constant	Value	Description
OK	0	OK
ERROR	1	Error

enum gyro_data_profile

Gyroscope data profile.

Constant	Value	Description
BALANCED	0	Data profile 1 (default). General-purpose configuration offering a solid compromise between resolution, responsiveness, and dynamic range. Suitable for a wide variety of environments and motion types.
FINE_MOTION	1	Data profile 2 (fine_motion). Prioritizes measurement precision with low noise and high stability. Uses a lower full-scale range and stronger filtering; intended for fine motion tracking and applications requiring maximum signal detail at the cost of responsiveness and increased susceptibility to vibration.
ROBUST	2	Data profile 3 (robust). Optimized for large shocks, fast rotations, and high-dynamic motion. Uses an extended full-scale range; intended to avoid saturation in harsh or demanding environments at the cost of increased noise and reduced resolution.