Author: Mikayla Lee

AER Telemetry over CAN ISO-TP

Overview

This system receives motor-controller telemetry over CAN ISO-TP, decodes it into strongly typed data, and forwards it for downstream processing. It also includes vCAN-based test utilities for CI.

Function: read_can_hardware

Purpose: Continuously reads and decodes telemetry packets from can0

Workflow:

• Opens an ISO-TP socket on can0 (source ID 0x666, destination ID 0x777)
• Retries socket creation on failure with a 1-second backoff
• Reads incoming packets asynchronously, validates packet length, and parses raw bytes into TelemetryData using Deku
• Captures a timestamp with now_ms() and forwards via send_message(data, ts)

Error Handling:

• Logs socket creation failures and malformed packets
• Logs packets with trailing bytes after decode
• Re-enters socket setup if packet reads stop or fail

Function: read_can

Dispatches to hardware ISO-TP reception (can0) or synthetic mode when the synthetic feature flag is enabled.

Function: read_can_synthetic

Publishes default TelemetryData at a ~1 ms interval for testing and CI. Logs throughput approximately once per second.

Struct: TelemetryData

Represents a fully decoded MCU telemetry packet received over CAN ISO-TP. Fields are decoded little-endian from a fixed-layout binary frame.