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UART Device Communication Protocol

Definition of protocol used when an UART communicating device is detected at an input port.

The communication used messages that consists of one or more bytes:

  FIRST BYTE IN MESSAGE MEANS
  ===========================

  bit 76543210
      ||
      00LLLCC0  SYS     - System message
      ||||||||
      ||000000  SYNC    - Synchronisation byte
      ||000010  NACK    - Not acknowledge byte
      ||000100  ACK     - Acknowledge byte
      ||LLL110  ESC     - Reserved for future use
      ||
      ||
      01LLLCCC  CMD     - Command message
      ||   |||
      ||   000  TYPE
      ||   001  MODES
      ||   010  SPEED
      ||   011  SELECT
      ||   100  WRITE
      ||   101
      ||   110
      ||   111
      ||
      ||
      10LLLMMM  INFO    - Info message (next byte is command)
      ||   |||
      ||   000  Mode 0 default   (must be last mode in INFO stream to select as default)
      ||   001  Mode 1
      ||   010  Mode 2
      ||   011  Mode 3
      ||   100  Mode 4
      ||   101  Mode 5
      ||   110  Mode 6
      ||   111  Mode 7
      ||
      ||
      11LLLMMM  DATA    - Data message
        |||
        000     Message pay load is 1 byte not including command byte and check byte
        001     Message pay load is 2 bytes not including command byte and check byte
        010     Message pay load is 4 bytes not including command byte and check byte
        011     Message pay load is 8 bytes not including command byte and check byte
        100     Message pay load is 16 bytes not including command byte and check byte
        101     Message pay load is 32 bytes not including command byte and check byte



  Messages From Device
  ====================

    Command messages:

      TYPE      01000000  tttttttt  cccccccc                                                                                    Device type

      MODES     01001001  00000iii  00000jjj  cccccccc                                                                          Number of modes

      SPEED     01010010  ssssssss  ssssssss  ssssssss  ssssssss  cccccccc                                                      Max communication speed

    Info messages:

      NAME      10LLLMMM  00000000  aaaaaaaa  ........  cccccccc                                                                Name of Device in mode MMM

      RAW       10011MMM  00000001  llllllll  llllllll  llllllll  llllllll  hhhhhhhh  hhhhhhhh  hhhhhhhh  hhhhhhhh  cccccccc    Raw value span in mode MMM

      PCT       10011MMM  00000010  llllllll  llllllll  llllllll  llllllll  hhhhhhhh  hhhhhhhh  hhhhhhhh  hhhhhhhh  cccccccc    Percentage span in mode MMM

      SI        10011MMM  00000011  llllllll  llllllll  llllllll  llllllll  hhhhhhhh  hhhhhhhh  hhhhhhhh  hhhhhhhh  cccccccc    SI unit value span in mode MMM

      SYMBOL    10011MMM  00000100  aaaaaaaa  aaaaaaaa  aaaaaaaa  aaaaaaaa  aaaaaaaa  aaaaaaaa  aaaaaaaa  aaaaaaaa  cccccccc    SI symbol

      FORMAT    10010MMM  10000000  00nnnnnn  000000ff  0000FFFF  0000DDDD  cccccccc                                            Format of data in mode MMM

    Data messages:

      DATA      11LLLMMM  dddddddd  ........  cccccccc                                                                          Data in format described under INFO MMM


    Messages from the device must follow the above sequence
    Devices with more modes can repeat "Info messages" once for every mode
    Highest "mode number" must be first
    NAME is the first in info sequence and is necessary to initiate a mode info
    FORMAT is last in info sequence and is necessary to complete the modes info
    Other info messages is optional and has a default value that will be used if not provided
    Delay 10 mS between modes (from FORMATx to NAMEy) to allow the informations to be saved in the brick


    # After ACK only DATA is allowed at the moment

    (Simplest device only needs to send: TYPE, NAME, FORMAT - if SPEED, RAW, PCT and SI are defaults)



  Messages To Device
  ==================

    Command messages:

      SPEED     01010010  ssssssss  ssssssss  ssssssss  ssssssss  cccccccc                                                      Max communication speed

      SELECT    01000011  00000mmm  cccccccc                                                                                    Select new mode

      WRITE     01LLL100  dddddddd  ........  cccccccc                                                                          Write 1-23 bytes to device

    # After ACK only SELECT and WRITE is allowed at the moment



  BIT Explanations
  ================

      LLL       = Message pay load bytes not including command byte and check byte
                  000   = 1
                  001   = 2
                  010   = 4
                  011   = 8
                  100   = 16
                  101   = 32

      CCC       = Command
                  000   = TYPE
                  001   = MODES
                  010   = SPEED
                  011   = SELECT

      MMM       = Mode
                  000   = Mode 0 default   (must be last mode in INFO stream to select as default)
                  001   = Mode 1
                  010   = Mode 2
                  011   = Mode 3
                  100   = Mode 4
                  101   = Mode 5
                  110   = Mode 6
                  111   = Mode 7

      iii       = Number of modes
                  000   = Only mode 0      (default if message not received)
                  001   = Mode 0,1
                  010   = Mode 0,1,2
                  011   = Mode 0,1,2,3
                  100   = Mode 0,1,2,3,4
                  101   = Mode 0,1,2,3,4,5
                  110   = Mode 0,1,2,3,4,5,6
                  111   = Mode 0,1,2,3,4,5,6,7

      jjj       = Number of modes in view and data log (default is iii if not received)
                  000   = Only mode 0
                  001   = Mode 0,1
                  010   = Mode 0,1,2
                  011   = Mode 0,1,2,3
                  100   = Mode 0,1,2,3,4
                  101   = Mode 0,1,2,3,4,5
                  110   = Mode 0,1,2,3,4,5,6
                  111   = Mode 0,1,2,3,4,5,6,7

      cccccccc  = Check byte (result of 0xFF exclusively or'ed with all preceding bytes)

      ssssssss  = Speed 4 bytes (ULONG with LSB first)

      tttttttt  = Device type (used together with mode to form VM device type)

      llllllll  = Floating point value for low (RAW/PCT/SI) value (used to scale values)
                  (Default if not received - RAW = 0.0, PCT = 0.0, SI = 0.0)

      hhhhhhhh  = Floating point value for high (RAW/PCT/SI) value (used to scale values)
                  (Default if not received - RAW = 1023.0, PCT = 100.0, SI = 1.0)

      nnnnn     = Number of data sets [1..32 DATA8] [1..16 DATA16] [1..8 DATA32] [1..8 DATAF]

      ff        = Data set format
                  00    = DATA8
                  01    = DATA16
                  10    = DATA32
                  11    = DATAF

      aaaaaaaa  = Device name in ACSII characters (fill with zero '\0' to get to LLL - no zero termination necessary)
                  (Default if not received - empty)

      dddddddd  = Binary data (LSB first)

      mmm       = Mode
                  000   = Mode 0
                  001   = Mode 1
                  010   = Mode 2
                  011   = Mode 3
                  100   = Mode 4
                  101   = Mode 5
                  110   = Mode 6
                  111   = Mode 7

      FFFF      = Total number of figures shown in view and datalog [0..15] (inclusive decimal point and decimals)
                  (Default if not received - 4)

      DDDD      = Number of decimals shown in view and datalog [0..15]
                  (Default if not received - 0)

  Example with info coming from a device with two modes
  =====================================================


      TYPE      01000000  tttttttt  cccccccc                                                type

      MODES     01001001  00000001  00000001  cccccccc                                      Mode 0 and 1, both shown in view

      SPEED     01010010  00000000  11100001  00000000  00000000  cccccccc                  57600 bits/Second


      NAME      10011001  00000000  'L' 'i' 'g' 'h' 't' '\0' '\0' '\0'  cccccccc            "Light"

      RAW       10011001  00000001  0.0 1023.0  cccccccc                                    RAW 0-1023

      SI        10011001  00000011  0.0 1023.0  cccccccc                                    SI 0-1023

      SYMBOL    10011001  00000100  'l' 'x' '\0' '\0' '\0' '\0' '\0' '\0' cccccccc          "lx"

      FORMAT    10010001  10000000  00000001  00000001  00000100  00000000  cccccccc        1 * DATA16, 4 figures, 0 decimals


      NAME      10011000  00000000  'C' 'o' 'l' 'o' 'r' '\0' '\0' '\0'  cccccccc            "Color"

      RAW       10011000  00000001  0.0    6.0  cccccccc                                    RAW 0-6

      SI        10011000  00000011  0.0    6.0  cccccccc                                    SI 0-6

      FORMAT    10010000  10000000  00000001  00000001  00000001  00000000  cccccccc        1 * DATA16, 1 figure, 0 decimals


      ACK


  Error handling
  ==============

  Before ACK:

  IF ANYTHING GOES WRONG - HOST WILL NOT ACK AND DEVICE MUST RESET !


  After ACK

  IF CHECK XOR FAILS - HOST WILL NACK
  IF FORMAT FAILS    - HOST WILL TRY SELECT 5 TIMES

  IF ABOVE FAIL      - ERROR IS SHOWN TO USER
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