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Author Topic: Looking for a PIC code development partner  (Read 27021 times)

G7MRV

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Looking for a PIC code development partner
« on: June 21, 2016, 07:15:54 PM »

Hi,

I am working on a project to provide a 'modern' remote 'VFO' control system for a 1980s vintage military HF manpack radio. The radio in question is the Clansman PRC-320.

The project will use Microchip PIC microcontrollers. One will act as an 'intellegent' bidirectional serial to parallel converter, to be embedded inside the radio. Its job will simply be to read the state of the synthesiser BCD control lines, or to set those lines, and will communicate with the remote device via a serial link. The other will act as the remote control, and will have the job of displaying the working frequency, selecting between A and B VFOs (purely a memory/logic task), reading a rotary encoder and various inputs, incrementing/decrementing the frequency and step etc etc, all the stuff needed to control an RF synthesizer in the way we are these days accustomed.

Now, Although I have the necessary radios and have performed the required modifications to access the control lines, and although I can build and integrate the PIC control system into said radios, I cannot for the life of me write the code! I have tried to learn to do so but have not got far, certainly not good enough to write the code needed for this project,

So, I am looking for a partner. Someone who can commit a little time to developing the necessary code. It shouldnt be too difficult. The inputs/outputs needed for the synthesizer are all 3v logic BCD and conform to a set of lookup tables. They can be tested with switches/LEDs in the absence of the radio. The key aspect for me is the serial link between the two devices, and the need for the 'local' device (the one in the radio) to have a LOT of I/O pins!

I would have to make some design specifications, such as what I require the controller to do, what features etc, and some suggestions, such as preferred ICs (due to the physical contraints inside the radio), but the implementation in code would be entirely the developers choice, and the credit for the code also. The whole project is to be 'open source' and eventually published for others to copy.

SO if you are a whiz with PIC microcontrollers, can implement a good serial data link between two of them, and are interested in commiting some time to a project of this sort, please drop me a PM, and we can discuss whats required,

Cheers
Martin G7MRV

AF6WL

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RE: Looking for a PIC code development partner
« Reply #1 on: June 22, 2016, 08:22:07 AM »

For the radio end, you might consider using some 74HC595 serial to parallel shift registers to drive the synthesizer BCD inputs.
If you really want to read the BCD dials, which seems a bit unnecessary, some 74HC165 parallel to serial shift registers would do it.

The result is a SPI compatible 4 wire bi-directional bus that can be connected to a remote uP.
If you want fast development consider using an Arduino - easy to add a LCD and rotary encoder.
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G7MRV

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RE: Looking for a PIC code development partner
« Reply #2 on: June 22, 2016, 06:53:43 PM »

For the radio end, you might consider using some 74HC595 serial to parallel shift registers to drive the synthesizer BCD inputs.

The only other remote control project ive ever come across for these radios used that approach. That required external ribbon cabling. One of the main aspects of my project is that the physical and operational integrity of the radio is not to be compromised. When the remote VFO control is not in use, the radio must operate normally. This means no external connections other than those already available (as it happens these radios have a pair of parallel audio ports, one of which I have repurposed for the remote connection. There is also very very little spare internal space. A VLSI uC SMT device will just about fit

If you really want to read the BCD dials, which seems a bit unnecessary, some 74HC165 parallel to serial shift registers would do it.

Absolutely required. The radio is designed for back pack use. The remote unit must be able to show the 'native' operating settings of the radio when it is not set for remote control (local/remote operation selected by the user on the remote unit)

The result is a SPI compatible 4 wire bi-directional bus that can be connected to a remote uP.
If you want fast development consider using an Arduino - easy to add a LCD and rotary encoder.

Arduino may be an option for the remote unit end. But it is far too big for the internal section.

It isnt quite as simple as just the BCD encoding. There are several other control lines to be handled by the system as well.

I have specified PICs as even though I cannot code them, I do at least understand them electrically and can implement the circuitry for them.

With many old boatanchor/mil surplus radios there is plenty of space inside for mods, and plenty of vents etc to bring control lines out. The PRC-320 is a highly compact and incredibly complex manpack. The space I have for the internal uC is about the size of a flat Li-ion HT battery!

The requirement for the radio to not only look original but to operate as original in the absence of the remote unit does put very tight constraints on the project architecture. The only thing that will set the radio apart from any other will be the loss of one of the audio connectors (although the same actual plugs and sockets are used!) The 7-pin connector gives me a 24v supply, ground and PTT, leaving me four data lines.

If your not familiar with these radios, you can see the work ive done so far on this one on my blog (you'll need to scroll down a few posts!  http://g7mrv.blogspot.co.uk/

AK0B

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RE: Looking for a PIC code development partner
« Reply #3 on: June 29, 2016, 09:13:22 PM »

check out the PICAXE its easy to program and cheap -  the basic processor is a pic chip

   www.picaxe.com

  Stan AK0B
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