Self-programming PICs

[Dan East]

Assuming the EPROM has already been loaded with a new binary image, is it possible to flash a PIC with the image in EPROM completely stand-alone?

Specifically what I want to do is send the PIC a new image via IrDA which it will store in EPROM. After checksum verification it will then reflash itself with that image.

It is acceptable to assume the self-flash routine would not be upgradable via this technique. IE that chunk of memory would be identical to the corresponding part in the new image.

Dan East

 

[Exo]

Yes, its possible, with a bootloader.

A bootloader is a piece of software you write yourself and get programmed into the pic the normal way... The bootloader is fixed and can only be changed in a normal programmer....

Thr bootloader can then get data from anywhere, and program the pic

 

[Nigel Goodwin]

As Exo says, this is called a bootloader, but what he didn't mention is that only certain PIC's are capable of doing it!.

The capability is clearly explained in the datasheets, the 16F876/7 series are some PIC's which have this capability.

 

[Dan East]

Okay, I see in the description that the 876 is "self programmable". Is there an easy way to determine which PIC models are self programmable? The 876 would be acceptable, except that it costs twice as much as an 819.

So basically I'm looking for the cheapest 16Fxxx self programmable PIC with an 8 MHz internal oscillator.

Dan East

 

[StupidDum]

check this out
https://www.microchipc.com/

 

[Exo]

Is there an easy way to determine which PIC models are self programmable?

check out the datasheets, there should be a topic wich handles data eeprom / program eeprom programming...
if if only handles data eeprom then its not a self programmable

 

[checkmate]

The concept of self-programming is really just the ability to use software commands to write to program memory. A bootloader is simply a program that dumps serial inputs into program memory, and then jumps to the starting address of the uploaded program.
Since the bootloader itself is a program, it will have to be programmed into the PIC with a programmer before it could work.

 

[falleafd]

May someone give a full list of safe programmable chips? It's necessary, because we used to work with some of them, and most of us don't know about all of them.

 

[evandude]

since you're comparing to an 819, i assume you just need an 18-pin PIC?

you might find the 16F88 is just what you want. 8mhz internal oscillator, 18 pins, and self-programmable. (among other things) basically just a step up from the '628. I don't know what sort of a price difference you'll be looking at though.

 

[Dan East]

At Mouser:
PIC16F819: $2.10
PIC16F88: $2.60

Much more reasonable price difference. Thanks!

Dan East

 

[evandude]

no problem. personally I'm in the process of switching over to using the F88 instead of the F628 in all my various projects. it's just got better EVERYTHING.

please, post here or let me know if this project works out for you. I am quite interested in doing something like this, probably with an external EEPROM and either IRDA or with those cheap RF TX/RX pairs.

 

[Timmymna]

For anyone looking for PICs with specific functions, number of pins etc
PICBasic have a good comparison chart which you can search though and narrow down to PICs with specific functions or view the entire list.
**broken link removed**

Hope that helps