AVR developer needs PIC help

I have sucessfully programmed the 16F688 and 18F2455 with a very simple programmer.

The basic idea is given at

(I used a different buffer but I suppose you can use anything you want as long as you are able to get 5 volts out(i.e., you can use TTL with pullup resistors, etc...).

I used the parallel port and WinPic

and it seems to work prefectly as far as those two pics are concerned. Write your code, assemble/compile it into a hex file, load it up in winpic and tell it to program the pic and your done. You will have to setup an interface which tells winpic what parallel port pins are what. Its pretty easy to do and explains it all in the help documents. I use

[Info] [ProgrammerControlLines] VppOnOff=!D2 VddOnOff=!D3

DataIn=ack DataOut=D7 DataOutWhileReading=0 OutEnable=!D6

ClockOut=D5 ClkEnable=!D4

and have the outputs appropriately hooked up to the buffer and then to the pic(the power pins control transistors which is necessary for the high voltage need to program the pic).

(You can add more Programmer Control Lines to WinPic to control things such as buttons and LEDS and such to add more functionality)

You would be supprised how easy it is so my advice is for you just to dive right in. Although I still have not yet been able to program the 18F4431 for some reason using the same method...

Some things to note are that in WinPic you need to select raise VDD before VPP on some PICS(look at the timing diagrams for them to know... the 16F688 needs it raised after and the 18F2455 needs it raised before).

Probably the hardest part of it is getting the parallel port output... I had to tear up an hold modem and rip its connector out and manually solder wires to the pins so I could interface it with my breadboard... I then used hot glue to secure the wires at the connection to the connector so they wouldn't wiggle and short out... its not pretty but seems to work.

I'm sure you could easily do this in a weekend if you wanted and have the parts.. its relatively easy connections(basicaly connect the dots). You will need about a 13V power supply though. I made a power supply that had 5,

12 and variable so it was pretty simple to use but if you know what a voltage regulator is and how to use it then it shouldn't be much of a problem.

Don't be scared to try it though... I had a lot of anxiety about it because I was afraid I would screw up the pics... but it went relatively smoothly(took me a couple of hours to do everything(excluding building the PS)). Another hint is that in WinPic you have to slow down the timing for some pics.... for the 18F2455 I can use it at 1us and for the 16F688 it has to be at 7us(you'll know what I'm talking about if you use winpic).

If you need any more help I'll step you through what I have to get you on your way.

Jon

I saw that. Byron's HLV programmer, but why it and not the LVP?

This line concerns me (from the web page): "Code memory size now up to 8192 words, data EEPROM memory up to 256 byte."

Seems like a 64kB 26XX would not work...

Maybe this high voltage thing is common in PIC land. I'm just worried my ISP programmer would fall over my work, the HV would hit something, and poof, there goes an IC.

I appreciate. I'm confident I can get things going, as I already program AVRs, I'd just rather not waffle around trying different programmers, SW packages, etc. Mainly the lack of details around which apps and programmers support the 18F series is what struck me as odd. The parts are not that new, are they? AVRGCC and avrdude typically have support for new AVR variants a month or two after Atmel gets them into production.

Jim

--
Jim Brain, Brain Innovations
brain@jbrain.com                                http://www.jbrain.com
Dabbling in WWW, Embedded Systems, Old CBM computers, and Good Times!

Not sure whats up with that. You can get the source code, which it says was done in Borland C V4... Might easily be able to re-compile it handle more. (But in the Code page under WinPic it has up to FFF0... so it might be able to handle it(and Data goes to about 1k))

Well, there is a low voltage programming mode for ICSP and such... I haven't use it yet but I think you have to atleast program it once in HV mode to set the LV programming bit... its all in the programming document... goto the pic your interested in and it will show some docs and one will be about FLASH programming for it.

The PIC's are pretty old I think.... There shouldn't be any problem programming them as they all use the same basic method. Looking at the programming specs it says

1.0 DEVICE OVERVIEW

This document includes the programming specifications

for the following devices:

. PIC18F2221 . PIC18F4221

. PIC18F2321 . PIC18F4321

. PIC18F2410 . PIC18F4410

. PIC18F2420 . PIC18F4420

. PIC18F2450 . PIC18F4450

. PIC18F2455 . PIC18F4455

. PIC18F2480 . PIC18F4480

. PIC18F2510 . PIC18F4510

. PIC18F2515 . PIC18F4515

. PIC18F2520 . PIC18F4520

. PIC18F2525 . PIC18F4525

. PIC18F2550 . PIC18F4550

. PIC18F2580 . PIC18F4580

. PIC18F2585 . PIC18F4585

. PIC18F2610 . PIC18F4610

. PIC18F2620 . PIC18F4620

. PIC18F2680 . PIC18F4680

Which is quite a wide range. I Still have not been able to program the

18F4680 and the 18F4431 for some reason. It might be an incompatibility with WinPic(yet it does list it as a supported device) and I'm fairly confident I don't have anything wired up wrong so there must be something I'm missing(but the document applies equally to the 18F2455 as to 18F4680, yet I can only get it to work with one of them... so maybe it does have something to do with WinPic).

AFAIK microchip doesn't bring out many new pics very often... they have a new 16-bit series comming out sometime and I suppose they are finished with the pic18 series(as far as new designs are concerned)... I could be wrong though.

Jon

I'll take a crack at it.

While PICs are quirky, they do bring a lot to the table.

Did you sample them? Microchip has an outstanding sample program.

That's a good game plan.

Are you planning on working in assembler initially?

Sounds like a pretty good plan.

It's a serial port programmer that requires a true serial port to operate properly. Michael is probably depricating it for that reason.

Mine are just simple code dumpers. I really prefer bootloaders and the Trivial programmers are a fast way to get a bootloader dumped. The ICSP version will do the job you require.

That's the new model. The expectation is that the programmer is such a central part of the development process that having a reliable, processor driven programmer handling everything is the way to go. But the creates the chicken/egg problem of how to develop a programmer to program the chip for the programmer.

I'm not sure there's a single solution there. winpicprog seems to have wide coverage of programmers and chip families. Microchip has made the process difficult because they keep rolling out different programming algorithms instead of just sticking to a single unified model.

The Pickit 2 fits this bill nicely.

That's debatable especially now that Microchip is rolling out the pickits.

It's designed that way.

Low voltage programming dedicates an I/O pin in the middle of port B for the low voltage programming signal. Most developers can't stand losing a pin in the middle of a full sized port.

Nope. There's everything from homebrew to professional. And developers are all over the map. One reason I push the Trivial line is that it's deliberately designed not to put a huge investment on time/resources. Also any parallel port programming software that can be configured can use it. So you can spend the 1/2 hour building and testing it and it'll serve your immediate needs.

Be aware that you need to ground the cable shield through a cap in order to get long cable operation. The AC termination scheme I set up isn't necessary.

Gotta go,

BAJ

Assuming I can program one of them... :-)

I saw that, but assumed it was a hassle, so I just ordered the parts. If all goes well, I'll sample something later, since you say it's pretty easy.

Would rather not :-). I can do PIC assembly (well, did SX assembly), but I suck at it. C is my lang of choice.

I noticed that. I've not had any trouble with the simple parallel port programmers on the AVR line, and I sometimes need to write special bootloaders that can be used by the item I am hooking the AVR to (non-standard pin usage, non standard protocols, etc... I know, but when you're doing an ATMEGA8 MLF and the interface from the PC is via some INT lines, that's what I have to use to make a bootloader).

I gather from your position that most folks build the simple programmer as a one time use to program a better programmer?

Yeah, and I really want a Linux solution, as I am migrating my development to Linux soon.

Is there Linux programmer support for it?

AHHH. You ought to note that on your page. That is a very useful piece of informaiton.

Can it serve all my needs :-)

If Pickit 2 has Linux support from someone, then I'll grab one. Otherwise, I'm afraid I'll wait, as I really want to jump full-time to Linux (for a host of other reasons).

Jim