Hardware Protocol Specification: Serial console (VT100-style CLI), software flow control¶

Version: illustrative
Physical Layer: 9600 bps, 8N1.0
Framing: delimited
Integrity Algorithm: none

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Description¶

Many console/CLI serial ports are wired with only TX/RX/GND -- no RTS/CTS lines exist to carry hardware flow control, so XON/XOFF (software, in-band) is the only option when the far end needs to pace output.

Command Catalog & Message Signatures¶

Category: GENERAL¶

`CommandLine` (Command ID: `0x00`)¶

Parameter	Type	Unit	Range / Constraints	Options
`text`	`string`	-	-	-

Device-Initiated Messages¶

`OutputLine` (Message ID: `OutputLine`)¶

Field Name	Type	Unit
`text`	`string`	-

Formal AsyncAPI 2.6.0 Specification¶

asyncapi: 2.6.0
info:
  title: Serial console (VT100-style CLI), software flow control
  version: illustrative
  description: Many console/CLI serial ports are wired with only TX/RX/GND -- no RTS/CTS
    lines exist to carry hardware flow control, so XON/XOFF (software, in-band) is
    the only option when the far end needs to pace output.
servers:
  serial_link:
    url: serial://tty/9600
    protocol: serial
    description: Physical UART Transport (9600 bps, 8N1.0)
    bindings:
      serial:
        baudRate: 9600
        dataBits: 8
        parity: none
        stopBits: 1.0
        framingType: delimited
        integrity: none
channels:
  omniuart/cmd/CommandLine:
    publish:
      summary: 'Send command CommandLine (ID: 0x00)'
      description: Dispatch CommandLine frame to microcontroller over serial line
      message:
        name: CommandLine_Message
        title: CommandLine Command
        payload:
          $ref: '#/components/schemas/CommandLine_Request'
  omniuart/telemetry/OutputLine:
    subscribe:
      summary: 'Unsolicited telemetry message OutputLine (ID: OutputLine)'
      description: 'Unsolicited telemetry message from device: OutputLine'
      message:
        name: OutputLine_Telemetry_Message
        title: OutputLine Telemetry
        payload:
          $ref: '#/components/schemas/OutputLine_Telemetry'
components:
  messages: {}
  schemas:
    CommandLine_Request:
      type: object
      properties:
        command_id:
          type: integer
          const: 0
          description: Opcode ID for CommandLine
        text:
          type: string
      description: Command payload for CommandLine
    OutputLine_Telemetry:
      type: object
      properties:
        text:
          type: string
      description: Device-initiated telemetry payload for OutputLine