Too Big of Picaxe?

[Graham Ogle]

My knowledge of PICs is limited to Picaxe chips so I wonder if people can tell me if this application is too big for a Picaxe?
I want to remotely control a radio by sending a control file to a Picaxe via a serial link. The Picaxe then reads the file and configures radios, modems and aerials appropriately. The file will probably be less than 100 bytes long. I can do this in BASIC, but don't want to have a PC dedicated to this task. Is this task too much for a Picaxe or should I look at a blank PIC and then program it via the Pic Programmer?
Any help/advice much appreciated.
Thanks
Graham

 

[Graham Ogle]

Sorry for the typo in the title. It should read "Too big for a Picaxe?"

 

[Bloody-orc]

hat and how needs to be configured? what the pic(axe) should do with all that equipment? hange the values of potentiometers?

 

[AllanBertelsen]

A Picaxe can be extended. That goes for memory, inputs and outputs. The most limiting factor is program memory.
How much does the logic in your program fill. In Picaxe manual 1 page 9 <A href='http://Www.rev-ed.co.uk/docs/picaxe_manual1.pdf' Target=_Blank>External Web Link</a> you can see the amount of memory for each picaxe. The X versions got a lot more than the others. So the question is. Is 600 lines enough for your logic?

Edited by - AllanBertelsen on 08/04/2006 09:49:55

 

[rfs]

As a matter of interest, which rig(s) are you planning to control?
I'd like to achieve the same, (eventually).
rfs

 

[Graham Ogle]

The rig is an FT817. The home location is excellent for HF, VHF and UHF, while my Air Cadet Squadron has a poor location and no room for aerials. If we can send a command file up to the picaxe, via a TNC, probably with CTCSS tones to indicate a command file, the hope is that the 817 can be configured for voice or data and the appropriate aerial selected. Not asking much is it!

 

[rfs]

Graham.
I&#8217;ve been looking at the CAT command/opcode sets.
FT-817 = 17. My old FT-840 = 24.
They look &#8220;axe-essible&#8221;.

The first &#8220;but, though, &#8230;.&#8221; is the Yaesu&#8217;s 4800,1s,8d,0p,2stop.

The Picaxe&#8217;s default is 8d, 1stop,
for the SERIN/SEROUT/SERTXD commands.

However, I&#8217;m sure that the &#8220;bit-bang brigade&#8221; could crack that.
(Try Hippy&#8217;s website and posts. Brain-hurting, but great reading.)

Your project sounds fascinating.
I&#8217;d be happy to QSY to email, to save clogging up forum space.
(And possibly incurring QRN.)

rfs

 

[hippy]

It has potential. There are two issues; getting the serial out from the PICAXE to the the comms kit and receiving the file over the air.

Sending data shouldn't be too much of a problem and can go up to 9600 on 08M and 18X. Needing extra stop bits is easy, just add a delay beteeen each byte sent.

Receiving the file is more challenging. You may just be able to squeeze it into the SFR(RAM) as a buffer. How the data to it arrives is the big query I have, PICAXE's are not brilliant with streamed back-to-back serial data at anything above moderate speeds.

One solution might be to choose a PICAXE which supports I2C, store all/many files in I2C Eeprom and then have a simpler command system which tells the PICAXE which file to select and send.

 

[Graham Ogle]

Thanks for all the ideas and hints. Does this forum support private email? If so, rfs, feel free to email me off forum.
At this stage it is just an idea I am evaluating, but I haven't found any great hurdles to be overcome. For faster PIC's or greater on board memory, I have access to the Picaxe serial pic programmer which could remove some of the problems. Thinking about the system today, two CTCSS tones could be used; one to identify the command file and the other to pass voice/data through the repeater system.
I think it is time I tried the serial input of the Picaxe and if it can read the file. I'll probably be back on here with some really basic questions in the next 10 minutes or so!
Graham