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Communication Protocol 🛰️

Overview​

This document describes the communication protocol between the PC (host) and the Delta6 end-effector firmware, including command formats, response formats, functional descriptions, and error handling mechanisms.

📱 Command Frame Format (PC → Firmware)​

FieldDescription
Start Byte0xAA, indicates the beginning of a frame
Command ByteOperation code (Calibration or Read)
ChecksumSimple additive checksum

Command Byte Values:

  • 0x01: Calibration Command
  • 0x02: Read Command

Checksum:
The checksum is calculated as the simple sum of the start byte and command byte, modulo 256.

📥 Response Frame Format (Firmware → PC)​

FieldDescription
Start Byte0xAA, indicates the beginning of a frame
Sensor 1 Data2 bytes (signed integer, calibrated angle)
......
Sensor 6 Data2 bytes (signed integer, calibrated angle)
Error Flags1 byte (each bit indicates a sensor read error)
Checksum1 byte (simple additive checksum)

Sensor Data:
Each sensor outputs a signed 2-byte integer representing the calibrated angle.

Error Flags:

  • 1 byte total.
  • Each bit corresponds to one sensor.
    If a bit is 1, the corresponding sensor encountered a read error.

Checksum:
The checksum is calculated as the simple sum of all bytes after the start byte.

🔧 Functional Details​

Calibration Function​

Upon receiving a Calibration Command (0x01), the firmware:

  • Reads the current angle values from all sensors.
  • Stores them as calibration offsets.

Read Function​

Upon receiving a Read Command (0x02), the firmware:

  • Reads the current sensor values.
  • Subtracts calibration offsets.
  • Sends the calibrated values along with error flags and checksum.

Error Handling​

In the updatePositions() function:

  • If a sensor read returns -1, the corresponding error flag bit is set.
  • Errors are reported in the response frame's error flag byte.

Data Integrity​

  • A simple additive checksum ensures data integrity.
  • CRC can be used for more robust error detection if needed.

📌 Notes​

  • Start byte 0xAA must always be included at the beginning of each frame.
  • Only two commands (0x01 and 0x02) are currently supported.
  • All multi-byte data are transmitted big-endian unless otherwise specified.

✅ This communication protocol ensures reliable, efficient interaction between the PC and the Delta6 firmware, enabling robust 6-DOF force-sensing operations.

Acknowledgment​

Some parts of the documentation and code were assisted by language models (OpenAI's ChatGPT) during their initial drafting. All content was subsequently reviewed and verified by the project authors.