RRUI

Presentation

RRUI is a software based on QT5/QML which aim is primary to display data from embbeded system. It is based on a really simple fixed-length protocol.

Protocol

Transport layer

This protocol can be used with different transport layers. It is a very simple protocol that relies on the underlying layer integrity.

Messages are grouped into packets. On IP layer, a packet is the network packet. On serial link, a packet is assumed for example when a 100ms pause is detected ; or with a checksumed frame with delimiters and length if needed. The packet entity helps to synchronize reception.

Messages content

All messages are 64 bits long (8 bytes). There can be several messages in each packet.

Byte 0 carries the type of data

• 0x00: Binary/boolean
• 0x01: int8_t
• 0x02: uint8_t
• 0x03: int16_t
• 0x04: uint16_t
• 0x05: int32_t
• 0x06: uint32_t
• 0x07: float (32 bits)

Byte 1 carries wanted action

• 0x00: Report a value (report)

  This one is used to report a value in its argument

• 0x01: Ask for a value (get)

  Ask for a on-shot value of a specific parameter (useful for sporadic information)

• 0x02: Set a value temporary (set)

  Set a value temporary, that is the new value is read by the application until a new value is updated by the application itself or another action. It also cancels the forced status

• 0x03: Force value (force)

  Force a value, that is the new value is read by the application whatever the application itself tries to update. A release action is needed to return to the normal operation mode.

• 0x04: Release a value (release)

  Cancels the force action. The forced value remains the one the application reads until a new value is updated by the application itself or another action.

• 0x05: Reload reset value (reload)

  Reload the value the variable had at boot or last one saved, ie the saved value.

• 0x06: Save value (save)

  Save value so that it will be loaded by default at next boot. It affects the reload command and cancels the forced status.

• 0x07: Export value periodically (export)

  Export value periodically. The period is set by the argument of the message read as an integer which sets the number of ignored loops, ie a pediod of rougly (arg+1)*10ms.

• 0x08: Arrêter l'export (unexport)

  Stop export of a value

Bytes 2 and 3 carry parameter number read as an integer in little-endian endianess.

Bytes 4 to 7 carry argument (often parameter value) read in little-endian endianess. If it is shorter than 32 bits, only lower significant bits are relevant, other are ignored. The entire field can be meaningless depending on the action, eg when a get action is used.