PIC Programmers WTD... Computer Controled Maxtrac

Post by **Bat Wing** » Wed Oct 17, 2001 8:28 pm

OK, now that I have your interest, here is what I am looking for...

With 800MHz Maxtracs so cheap these days, and the lack of cheap, quality, computer controlled scanners, I need someone to develop a PIC to interface a computer to the PLL in a Maxtrac (receive only).

This would enable all those Trunker users out there to drive the receiver in a Maxtrac with a their PC.

It should be just a matter of converting the RS-232 frequency data output by the PC into the data to load the PLL in the Maxtrac. Break the control of the PLL from the logic board, insert the data from the PIC and you should be set.

But alas, I am not a PIC programmer, so need someone to develop the code and interface for beta testing.

Any takers?

Bat

Mdjonston · Post by **Mdjonston** » Sat Oct 20, 2001 11:51 pm

Mdjonston · Post by **Mdjonston** » Sat Oct 20, 2001 11:54 pm

Email me at [email protected] with some more info regarding what you need to be done, info on PLL, anything that is relevant and we will be able to do something for you..
Mike

radionova327 · Post by **radionova327** » Wed Jan 16, 2002 10:05 am

Any luck here?

The PLL section of my copy of the service manual seams to be full of errors. I see 0's, 1's and 2's in what I believe should be a binary. I see divisions which there result dose not much mine, ect...

I will try to manualy feed in the DATA/CLK/EN lines and see if it works.

Post by **Bat Wing** » Thu Jan 17, 2002 8:02 am

On 2002-01-16 13:05, radionova327 wrote:
Any luck here?

The PLL section of my copy of the service manual seams to be full of errors. I see 0's, 1's and 2's in what I believe should be a binary. I see divisions which there result dose not much mine, ect...

I will try to manualy feed in the DATA/CLK/EN lines and see if it works.

Yes, there are some errors in that page.

We have a prototype that appears to be working, just need to do some final testing.

Bat

radionova327 · Post by **radionova327** » Tue Jan 22, 2002 9:31 am

OK, I have made this project my senior project at school. If you don't mind, I have some questions for you. I have been unable to read the divided reference freq on pin 13, even on a working radio. Have you been able to do so? I do get 12.5KHz on pin 12 (on a working radio). I have tired to hand program the reference counter with 1152 and reading nothing at pin 13. Pin 12 does not work either but I may need to have the A and N counters programed for that to work.

Any thoughts?

Thanks
Tom

Mdjonston · Post by **Mdjonston** » Thu Jan 24, 2002 12:20 am

Tom,
I have been working on this project with Bat. I would suggest going to Motorola at
http://e-www.motorola.com/webapp/sps/si ... 9843136070
or
search for datasheet on chip MC145158-2.

If you read the datasheet you will get a better understanding of the timing to program the freq. synth.

Mike.

radionova327 · Post by **radionova327** » Fri Jan 25, 2002 9:31 am

Thanks Mike,

I have read the datasheet. I have sent the serial data to set the R divider output at pin 13 to be 12.5KHz but I can seam to measure anyhing there. Even on a non modifed working radio, I can not measure anything there. Maybe I'll program up all three counters and see if it will receive where I think it will and forget about pin 13.

Thanks,
Tom

franko · Post by **franko** » Sun Apr 18, 2004 4:26 pm

[quote="Bat Wing"]

With 800MHz Maxtracs so cheap these days, and the lack of cheap, quality, computer controlled scanners, I need someone to develop a PIC to interface a computer to the PLL in a Maxtrac (receive only).

Hi all,

I would like to know if anyone ever got this working. I've just started programing PICs and remembered seeing this and wanted to see if a Maxtrac could be set up to be controlled by "Trunker".

If anyone has any info on this, please let me know.

Thanks and best regards,
Franko

franko · Post by **franko** » Sun Apr 18, 2004 4:29 pm

I appologize, I did not mean for the entire thread to be posted.Just the part with the quote and my question.

I screwed up

FC

EKS · Post by **EKS** » Sun Apr 18, 2004 8:35 pm

I've done a bunch of PIC work in the past. I guess I can help if there is still a need.

franko · Post by **franko** » Tue Apr 20, 2004 3:56 pm

EKS, thanks for your reply.

If it is possible to program a PIC to have Trunker control a maxtrac 800, can you give me some guidance on how to do this?

This seems like something many here might find useful, especially me.

Thanks much,
FC

EKS · Post by **EKS** » Wed Apr 21, 2004 8:07 am

franko wrote:EKS, thanks for your reply.

If it is possible to program a PIC to have Trunker control a maxtrac 800, can you give me some guidance on how to do this?

This seems like something many here might find useful, especially me.

Thanks much,
FC

I don't see why it couldn't. It's just a matter of getting the rs232 (or whatever it is) signal from trunker and having it translate it to the radio, overriding the current programming. All you need is a recieve frequency.

I'd probably have to start from scratch on this. I was hoping that someone had started this already so it would be easier to contribute. I'll try putzing around with it probably next week. I've got a couple trunking maxtracs just waiting to be gutted. I just need to get some stuff out of the way first.

franko · Post by **franko** » Thu Apr 22, 2004 7:28 am

Thanks EKS,

I too have been hoping that Bat Wing or anyone else involved with this might see this and respond also. Hopefully that may still happen.

Reading the Trunker documentation, it does look like it puts out RS232 to control the RX freq,but I have no clear Idea as to how to implement this to the Maxtrac.

Thanks again,
FC

cbrock · Post by **cbrock** » Fri Apr 23, 2004 1:34 pm

Some time ago I wrote some PIC code to decode what channel a trunked maxtrac was being sent too by the trunking controller - great for troubleshooting audio holes, as part of that code I developed an Excel spreadsheet to determine the bits that were loaded into the synth. I can make both the PIC code and excel spreadsheet advalible to anybody that wants it.

Post by **Bat Wing** » Sun Apr 25, 2004 9:22 pm

Its nice to see this old thread come back to life.

All of the work that was done on this thread can be downloaded at http://www.batlabs.com/arc/maxcomp.zip. Beware that this is almost a 4mb zip file. Also, give it about 24hours to reach all of the mirrors.

Everything that was accomplished is in there, as well as datasheets and schematic bits for the PLL in the Maxtrac.

IIRC, Trunker will spit out the tune frequency in ASCII. The plan was to grab this ASCII with a PIC, figure out what to program the divisors in the PLL chip with, and load up the PLL in the Maxtrac. We cut the lines between the micro in the Maxtrac and the PLL and used the PIC to program it instead.

I believe that we actually did get it working, but it wasn't reliable. When it worked, it programmed fine, but sometimes it would go off into outer space and get lost and stop working.

I have thought about this project over the years, and have actually thought about working on it again in the near future, this time with a bit more knowledge under my belt.

One think that has bugged me is that it would seem to work and then just die. One think I never had a chance to check was if there were some other pins that needed to be taken care of, like the PIN Shift pin, or T/R pins, or whatever else is working in there. I suspect PIN Shift may have been part of the problem.

If there are some PIC/PLL experts out there, this would be a cool mod to be able to make to a Maxtrac. As everyone knows, the receiver will blow away any scanner. The project shouldn't be that complex, its just a matter of writing the code to capture the ASCII from the PC, to a conversion, and spit it out to the radio. Of course it may have to be quick if the frequency is changing quite often, but it shouldn't be too bad to handle.

I'm not sure if doing actual calculations to figure out the N and A values is the way to go, or, depending on the PIC used, if a look-up table would be quicker. There are only a pre-defined number of frequencies in the channel plan for the 800MHz band. I'll leave that to the coder's to decide.

Cheers,

Bat

franko · Post by **franko** » Mon Apr 26, 2004 4:59 pm

Bat Wing,

I want to thank you and all involved with this for not only all the time and hard work that you put into this great idea,but also for making it available here.

I am looking forward to getting it working with my setup.

Much thanks and best regards,

Franko

RADIOMAN2002 · Post by **RADIOMAN2002** » Tue Apr 27, 2004 4:33 am

I think that you have tackled one heck of a project. I also would like to see it work. One thing I have not seen in the posts, is that I belive, even though I could be wrong, the channels for the 800 plan are hidden somewhere in the Maxtrac radio firmware program itself. I don't know if it would be easiser to get to that info for the radio to chanege channels or how you are doing it by direct manipulation of the PLL.

WB2IID · Post by **WB2IID** » Tue Apr 27, 2004 8:22 am

I believe that we actually did get it working, but it wasn't reliable. When it worked, it programmed fine, but sometimes it would go off into outer space and get lost and stop working.

Did you look at the PLL lock detect line when this happened? In my experience, stray electrical impulses - static discharge, switching on/off nearby electrical equipment, etc. - can cause a PLL to "lose its mind" and stop working.

To prevent this make sure you have as much filtering on the PLL data and chip select lines as possible without affecting rise times, and to make the leads as short as possible. It also may be worth monitoring the lock detect line with the PIC and re-loading the PLL with the last frequency if an out-of-lock condition is seen.

Just my .02.

Joe

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