[aprssig] APRS telemetry and the PIC 16F877A

[Andrew Rich]

Thank you David this is helpfull.

Maybe one day we will have a PIC in space and a radio !

I am fluent with assembly and have no probs with the 16F877A data thats
fine.

Its the AX25 implementation I can not get my brain around.

I know Scott has a packet shooter ? I was even considering that as well. 

I don't see why I should comit a TNC or D700 just for a simple task.

We have around 30 cheap handhelds, bought for another project on VHF. 

I have made the 16F877A do RTTY but that was as far as I got.

I am using MPLAB and have a programmer. I just ordered some 16F877A boards
made up from futurelec.

I notice that PIC's are now come with a 10 Mb LAN interface as well. Soon we
will have TCP/IP capable TNC's with IP addresses !

When I get a house, I will play with automation, such as sattellite antenna
arrays etc. I am dabbling with SOLAR panels, hence I recently ordered some
opentrackers for telem of volts and temp.

Cheers Andrew

-----------------------------------------
Andrew Rich
Amateur radio callsign VK4TEC
email: vk4tec at tech-software.net
web: http://www.tech-software.net
Brisbane AUSTRALIA 

  -----Original Message-----
  From: Dave Baxter [mailto:dave at emv.co.uk]
  Sent: Friday, 26 January 2007 9:57 AM
  To: vk4tec at tech-software.net; TAPR APRS Mailing List
  Subject: RE: [aprssig] APRS telemetry and the PIC 16F877A


  Easy!...  (Reletively at least!)

  Google for SOTT, or "Son of Tiny Trak"  The code ports easily to the F877,
and as it's in C, is relatively easy to manipulate.  Somewhere I have one
such already programmed.  I know some people were also looking into using
the PWM system to output the tones.  Likewise, the PWM capture logic to
receive and decode them, for all I know they got it working, or maybe not.

  However, as above, the SOTT code goes easily into the F877.  If I can do
it, anyone can!...

  The one nice thing about PIC's, is for the same series of CPU, (8 or 16
bit) the code changes very little between devices in the same family.  Most
is figureing out the config settings, and port naming conventions.
Sometimes you can have just too many IO functions to choose from.  The F877
is one such chip.  Just because it has ASYNC/SYNC serial IO, doesnt mean you
*have* to use it.  Hence, code from lesser chips that do all that bit by bit
(Bit/Bang) will still run just fine.

  If you go and download the MPLAB toolsuit (for free!)  and the free but
limited version of HiTech C compiler, you'll be OK.  Mind you, by now I
expect the code has been ported to one of Microchip's C compilers.  There
are dozens of others of course.

  Other choices, there are several PIC based TNC's about, with freely
available source code, both C and assembler, also both regular packet, and
APRS versions too.

  There is nothing wrong with the Atmel chips, but the CPU architecure you
could argue harks backwards in time, though they can be very low power, and
very fast running!  And of course if you have already worked with the Intel
805x series chips, the learning curve could be relatively shallow.

  PIC's and RISC archetcture, looking forward by comparison?  You choose,
based on what you have, and what you can get for free!

  Have Fun..

  Dave G0WBX.



----------------------------------------------------------------------------
--
  From: Andrew Rich [mailto:vk4tec at tech-software.net]
  Sent: Wed 24/01/2007 20:08
  To: ozaprs; Aprssig
  Subject: [aprssig] APRS telemetry and the PIC 16F877A


  Gudday

  I know of the MIM project, but I would like to issue a challenge to the
smarties.

  I have a 16F877A, which has at least 6 A/D and as many ports of logic.

  What I want to do is make the 16F877A PIC send APRS telem.

  Anyone done it ? Interested in coding it ?

  Andrew.
  -----------------------------------------
  Andrew Rich
  Amateur radio callsign VK4TEC
  email: vk4tec at tech-software.net
  web: http://www.tech-software.net
  Brisbane AUSTRALIA 


  This mail has been scanned by Palmer Cook Computer Services Limited.
www.palmercook.co.uk

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