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Command Reference

Commands are encoded, not sent, by this library. Each oscp_cmd_* function writes an ASCII command into a caller-owned buffer, framed for the transport selected at function call; Returned bytes are transmit separatly by the caller.

uint8_t cmd[32];
size_t  len = 0;

if (oscp_cmd_config(cmd, sizeof(cmd), &len, OSCP_TRANSPORT_RS422) == OSCP_OK) {
    /* Transmit as-is */
    platform_dependant_rs422_write(cmd, len);
    /* Good reliability habit to add a slight delay between commands */
    platform_dependant_delay_ms(10);
}

uint8_t cmd[32];
size_t  len = 0;

if (oscp_cmd_config(cmd, sizeof(cmd), &len, OSCP_TRANSPORT_CANFD) == OSCP_OK) {
    /* Require 0x6FC CAN Command ID and DLC padding */
    platform_dependant_canfd_write(0x6FC, cmd, len);
    /* Good reliability habit to add a slight delay between commands */
    platform_dependant_delay_ms(10);
}

Buffer sizing

A 32-byte buffer is sufficient for every command in the library and can be used for easier handling.

How framing depends on transport

Every command function takes a trailing oscp_transport_t argument:

Transport Encoding
OSCP_TRANSPORT_RS422 ASCII payload is COBS-encoded and terminated with a 0x00 delimiter. Transmit as-is.
OSCP_TRANSPORT_CANFD Raw ASCII payload only. Caller set the OSCP CAN command identifier (0x6FC) and DLC. The controller only frames the message. No COBS, no delimiter.

Command classes

Commands differ in whether the unit replies and in which state they are valid.

Catching Replies

Replies arrive back through the parser as OSCP_FRAME_CMD_* frame types, defined specificaly for the C Library. In the case of CAN-FD transport, they can be identified straight through the CAN ID 0x6FD.

Class Reply? Valid state
Silent / ANY None Any state
Silent / CONFIG None CONFIG only
Ack / OPERATING Reply expected OPERATING only
Ack / CONFIG Reply expected CONFIG only

Command catalogue

Every function shares the prototype shape oscp_err_t oscp_cmd_X(uint8_t *cmd, size_t cmd_max_len, size_t *cmd_len, [args,] oscp_transport_t transport). The wire column shows the ASCII actually emitted (before transport framing such as COBS).

Silent - valid in ANY state
Function Wire Purpose
oscp_cmd_reset RESET Reset the unit
Silent - valid in CONFIG state
Function Wire Purpose
oscp_cmd_exit EXIT Leave CONFIG state back to OPERATING state
oscp_cmd_refs REFS Restore factory settings and reset the unit
Ack - valid in OPERATING state
Function Wire Purpose
oscp_cmd_config CONFIG Enter CONFIG state
Ack - valid in CONFIG state
Function Args Wire Purpose
oscp_cmd_suf - SUF Get a startup frame
oscp_cmd_of oscp_frame_sel_t OF<x> Get a specific output frame
oscp_cmd_om oscp_om_sel_t OM<x> Set operating mode
oscp_cmd_enable_oft oscp_frame_sel_t EOFT<x> Enable an output frame type
oscp_cmd_disable_oft oscp_frame_sel_t DOFT<x> Disable an output frame type
oscp_cmd_drg oscp_gyro_dr_t DRG<nnnn> Gyroscope dynamic range
oscp_cmd_dra oscp_accel_dr_t DRA<nn> Accelerometer dynamic range
oscp_cmd_dri oscp_incl_dr_t DRI<n.n> Inclinometer dynamic range
oscp_cmd_enable_mcorr - EMCORR Enable misalignment correction
oscp_cmd_disable_mcorr - DMCORR Disable misalignment correction
oscp_cmd_wr oscp_usr_reg_t, uint32_t WR<REG><8·hex> Write a user register
oscp_cmd_save - SAVE Persist configuration

Argument enumerations

Frame selector - oscp_frame_sel_t

Used by oscp_cmd_of, oscp_cmd_enable_oft and oscp_cmd_disable_oft.

Enum Wire char Frame
OSCP_FRAME_SEL_RAW R Raw
OSCP_FRAME_SEL_EULER E Euler
OSCP_FRAME_SEL_QUATERNION Q Quaternion
OSCP_FRAME_SEL_ROT_MATRIX M Rotation matrix
OSCP_FRAME_SEL_GNSS G GNSS
OSCP_FRAME_SEL_DEBUG D Debug - oscp_cmd_of only

OSCP_FRAME_SEL_DEBUG is oscp_cmd_of-only

Passing OSCP_FRAME_SEL_DEBUG to oscp_cmd_enable_oft or oscp_cmd_disable_oft returns OSCP_ERR_INVALID. Debug frames are not meant to be sent periodically and are only receivable in CONFIG state, on-demand.

Operating mode - oscp_om_sel_t

Used by oscp_cmd_om.

Enum Wire char RAW ODR GNSS ODR Others ODR
OSCP_OM_IDLE I 0 Hz 0 Hz 0 Hz
OSCP_OM_LOW L 100 Hz 1 Hz 100 Hz
OSCP_OM_MEDIUM M 500 Hz 1 Hz 100 Hz

Gyroscope dynamic range - oscp_gyro_dr_t

Used by oscp_cmd_drg.

Enum Range
OSCP_GYRO_DR_125DPS ±125 °/s
OSCP_GYRO_DR_250DPS ±250 °/s
OSCP_GYRO_DR_500DPS ±500 °/s
OSCP_GYRO_DR_1000DPS ±1000 °/s
OSCP_GYRO_DR_2000DPS ±2000 °/s
OSCP_GYRO_DR_4000DPS ±4000 °/s

Accelerometer dynamic range - oscp_accel_dr_t

Used by oscp_cmd_dra.

Enum Range
OSCP_ACCEL_DR_2G ±2 g
OSCP_ACCEL_DR_4G ±4 g
OSCP_ACCEL_DR_8G ±8 g
OSCP_ACCEL_DR_16G ±16 g

Inclinometer dynamic range - oscp_incl_dr_t

Used by oscp_cmd_dri. Enum values are in tenths of g.

Enum Range
OSCP_INCL_DR_0G5 ±0.5 g
OSCP_INCL_DR_1G0 ±1.0 g
OSCP_INCL_DR_2G0 ±2.0 g
OSCP_INCL_DR_3G0 ±3.0 g

User registers - oscp_usr_reg_t

Used by oscp_cmd_wr. The value is written as 8 uppercase hex digits.

Register mnemonics
Group Mnemonics
Gyroscope bias GXB, GYB, GZB, GOB (GOB = optical gyro, optical-based models only)
Accelerometer bias AXB, AYB, AZB
Inclinometer bias IXB, IYB
Magnetometer bias MXB, MYB, MZB
Magnetometer calibration matrix MXX…MZZ (9 entries)
AHRS fusion FCO (convention), FHS (heading source), FRT (recovery period), FGA (gain), FAR (accel rejection), FMR (mag rejection)
Gyroscope filters GFI (enable bitmask), GLP (low-pass), GHP (high-pass)
Accelerometer filters AFI (enable bitmask), ALP (low-pass), AHP (high-pass)

Enum members are named OSCP_USR_REG_<MNEMONIC>, e.g. OSCP_USR_REG_FGA.

/* Write AHRS fusion gain register */
oscp_cmd_wr(cmd, sizeof(cmd), &len, OSCP_USR_REG_FGA, 0x3F800000u, OSCP_TRANSPORT_RS422);

Typical configuration sequence

  1. oscp_cmd_config - enter CONFIG (from OPERATING), stopping periodic data output
  2. oscp_cmd_om / oscp_cmd_drg / oscp_cmd_dra / oscp_cmd_enable_oft … - apply settings
  3. oscp_cmd_exit - return to OPERATING state, enabling periodic data output

Working Code

See the command-sending example for working code.

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