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Protocol

The communication protocol with the SP Pro appears to consist of requests for blocks of memory, with knowledge of the structures in that memory to be reimplemented by the requested.

Memory space

Memory is addressed as 2 byte words.

Memory of interest appears to be within the 0xa000 - 0xafff range.

Messages

Query

A query request consists of:

TLAAAACC

where:

  • T is the message type - Q for Query.
  • L is a byte indicating the number (length) of 2 byte words to return (0x00 will return 1 word).
  • AAAA is a little endian word address (shifting the address by 1 shifts by 2 bytes).
  • CC is a Cyclic Redundancy Check.

A query response consists of:

  • TLAAAACC the exact bytes from the query (including CRC).
  • MM the requested memory (the number of 2 byte words specified by L + 1).
  • CC CRC of the query + memory.

It's possible to request between 0-255 bytes of memory,

Write

A write request consists of:

TLAAAACCDDCC

where:

  • T is the message type - W for Write.
  • L is a byte indicating the number (length) of 2 byte words to be written.
  • AAAA is a little endian word address (shifting the address by 1 shifts by 2 bytes).
  • CC is a Cyclic Redundancy Check (everything to the left).
  • DD is the data to write, between 1 and 256 words (as specified by L + 1).

Example Messages

Hello

Prior to authentication SP LINK sends a request for 0 words from 0xa000 and the SP Pro will respond with the appropriate CRC calculation.

E.g:

Query:    0x510000a000009d4b
            TTLLAAAAAAAACCCC
Response: 0x510000a000009d4b0100d819
            TTLLAAAAAAAACCCCMMMMCCCC

Authentication

TODO!