Hardware Protocol Specification: M-Bus (EN 13757-2/3), long/control frame

Version: EN 13757-2
Physical Layer: 300 bps, 8N1.0
Framing: binary
Integrity Algorithm: sum8

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Description

START L L START C A CI DATA CHECKSUM STOP -- the length is sent twice and the start byte repeats after it, both as on-wire redundancy checks; a STOP byte closes the frame after the checksum too.

Command Catalog & Message Signatures

Device-Initiated Messages

LongFrame (Message ID: LongFrame)

Field Name	Type	Unit
cField	uint8	-
aField	uint8	-
ciField	uint8	-
data	bytes	-

Formal AsyncAPI 2.6.0 Specification

asyncapi: 2.6.0
info:
  title: M-Bus (EN 13757-2/3), long/control frame
  version: EN 13757-2
  description: START L L START C A CI DATA CHECKSUM STOP -- the length is sent twice
    and the start byte repeats after it, both as on-wire redundancy checks; a STOP
    byte closes the frame after the checksum too.
servers:
  serial_link:
    url: serial://tty/300
    protocol: serial
    description: Physical UART Transport (300 bps, 8N1.0)
    bindings:
      serial:
        baudRate: 300
        dataBits: 8
        parity: even
        stopBits: 1.0
        framingType: binary
        integrity: sum8
channels:
  omniuart/telemetry/LongFrame:
    subscribe:
      summary: 'Unsolicited telemetry message LongFrame (ID: LongFrame)'
      description: 'Unsolicited telemetry message from device: LongFrame'
      message:
        name: LongFrame_Telemetry_Message
        title: LongFrame Telemetry
        payload:
          $ref: '#/components/schemas/LongFrame_Telemetry'
components:
  messages: {}
  schemas:
    LongFrame_Telemetry:
      type: object
      properties:
        cField:
          type: integer
        aField:
          type: integer
        ciField:
          type: integer
        data:
          type: string
          contentEncoding: base64
      description: Device-initiated telemetry payload for LongFrame