RE: Re: xAP and how to interface to a Pic Micro?

["Kevin Hawkins" <lists@xxxxxxxxxxxxxxxxx>]

> -----Original Message-----
> From: Gary [mailto:questuk1@xxxxxxx]
> Sent: 06 June 2004 14:28
> To: xap_automation@xxxxxxx
> Subject: [xap_automation] Re: xAP and how to interface to
> a Pic Micro?
>
> I will be writing the software using PICBASIC, i can do
> asm if needed?

You might want to do this for speed or codesize but you could start with
PicBasic and see how you go - I would recommend as large a PIC as possible
to start with and then downsize when you get to optimisation and know the
likley codesize needed.

>
> Can anyone tell me the timing of the transmitted data, is
> it anything like RS232 data?

The data going out the serial port is standard RS232 asynchronous data and
so can be handled within PICBasic. xAP is just an 'on the wire' software
protocol it doesn't in any way define the physical layer so you can choose
your own serial data speed and format. It could be RS232 422 485, optical,
radio , Ethernet, synch,  asynch ....your choice ! Standard RS232
asynchronous is fine (depending on network traffic loading you would
probably go for the fastest speed possible).


>
> also what exactly has to be sent out and received for xAP
> to identify the PIC?

You have to send and receive the xAP messages as defined in the xAP
specfication document -

http://tinyurl.com/zg4l

message starts with

xap-header
{
..... etc for example...

>
> Just a brief overview so i can see how much coding will be
> required!

A 'reasonable' amount I would say depending on how full a xAP
implementation
you want to implement - for example wildcarding support takes time - what
will the PIC be doing and what other devices will you want it to interact
with ??  You should also take a look at the BSC document available here as
a
PDF ( so it may take a while to load)

http://tinyurl.com/2ceno

This is also in the files area of the Yahoo xAP Developer Group as a Word
document

http://groups.yahoo.com/group/xAP_developer/files/

- BSC handles very elegantly most 'Basic' devices schema wise.


>
> Thanks Gary
>
> PS: I did do search for PIC  but didn't turn up anything?
> am i doing something wrong, as im sure there should be
> some on here?

Take a look at Stuarts post of today  - also did you check the xAP
Developer
list too ?

Kevin


>
> --- In xap_automation@xxxxxxx, "Kevin Hawkins"
> <lists@u...> wrote:
> > Hi Gary,
> >
> > 	The main 'bible' you will need is the xAP v1.2 spec document
> > available here..
> >
> >
> http://www.xapautomation.org/modules.php?name=xAP_Content&p
> a=showpage&pid=xa
> > pcurrent
> >
> > 	There are a couple of people who have implemented xAP
> on a PIC, take
> > a search back through this list and also the xAP
> Developer list for
> 'PIC'
> > and I think it will pull out the posts. I have done some
> work on the
> Rabbit
> > in C and Ian has used the Atmel processors. In addition
> Patrick did
> > some work on a PIC xAP library - I am not sure how
> evolved that code
> > is but I believe it is quite efficient at under 1K in
> size so that
> > would be very helpful as a starting point. What are you
> programming the PIC in ??
> >
> > 	The tools to connect the PIC to the PC - ie a PC based
> bridge program
> > I think are already available again with one of Patricks
> applications.
> > Depending on the volume of data you envisage sending,
> the serial link
> > speed and on which network transport the other devices
> will be
> > located you might want to apply some filtering to the bridge
> implementation.
> >
> > 	Kevin
> >
> >
> >    > -----Original Message-----
> >    > From: Gary [mailto:questuk1@h...]
> >    > Sent: 06 June 2004 11:56
> >    > To: xap_automation@xxxxxxx
> >    > Subject: [xap_automation] xAP and how to interface
> to a Pic Micro?
> >    >
> >    > Hi all,
> >    >
> >    > I like what your doing with xAP, I would like to
interface
> >    > a PIC micro via the PC RS232 port then to xAP?
> >    >
> >    > What are the specs etc I need to achieve this?
>