[OpenTRV-dev] XAP

[Damon Hart-Davis]

Except that anything beyond a simple binary format will likely tax a uC beyond endurance, especially for parsing.

A trivial CLI on the PICAXE that I'm working on right now has taken 25% of my available code space and makes MS-DOS 1.x look a little over-friendly!

Rgds

Damon

On 3 Apr 2013, at 14:39, Bruno Girin wrote:

> MQTT doesn't specify a message format so you could very well use the XAP message format over MQTT.
> 
> Which reminds me, I need to add the PoC code I came up with to the source tree.
> 
> Bruno
> 
> On Tue, 2 Apr, 2013 at 4:26 PM, Thomas Hood <EMAIL ADDRESS HIDDEN> wrote:
>> 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
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