[OpenTRV-dev] XAP

[Thomas Hood]

On Tue, Apr 2, 2013 at 5:16 PM, Mike Stirling <EMAIL ADDRESS HIDDEN> wrote:
> I never really understand the logic behind projects that say they are
> targetting low-end embedded and then go on to develop a protocol in
> human-readable ASCII, or worse, XML!

At http://www.xapautomation.org/index.php?title=Protocol_definition I
found some explanation for this. I quote with a little editing for
readability:

Each name-value pair within the message block is defined by a keyword,
a delimiter, a value and a terminator. [...] The delimiter determines
the method of value encoding.

'=' (equals sign, ASCII character 61 decimal) indicates that a value
is encoded as an ASCII string. This is the preferred encoding format.

'!' (pling, ASCII character 33 decimal) determines that a value is
encoded as an ASCII hex representation. This allows the broadcast of
raw binary data. Whilst unavoidable under certain circumstances, its
use is discouraged because of the issues with portability (numeric
representations differ across processor types).

-- 
Thomas