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peterk · Guest

Maybe you need to think about the AVR instead. That has a keyfob
programmer available. Some nice stuff for AVR and PIC on this site
https://www.kanda.com/productnews.php3.

One approach that is in use at hundreds of locations in the UK is
update by satellite. Data is embedded in the TV blanking interval and
decoders with AVRs pull out the code and can reprogram themselves. If
you choose a self-programming AVR then if you can get data to it then
you can reprogram it.

Peter

matt@avisaro.com · Guest

By using a "RS232 to Compact Flash" module, you could store the
programming data onto a portable memory card, rather than on a Laptop.

Avisaro (I work for them) build those modules:
www.avisaro.com/html/speicher_module.html

You can read and write file over the serial line (RS232) by using
simple "AT" commands. Like: at+open flash.s19 would open the file
"flash.s19" for read and with at+datastream the content of the file
will be send over the serial port. They use the standard PC file
format.

If you have a "self programming" part like Byron suggest, you could
connect the module more or less directly. Or you use a small controller
which contains the programming algorithm and which uses the RS232 to CF
module to get the data. A simple encryption algorithm could be
implemented in this case as well.

- Matt
You can contact me directly if you need an Englisch speaking person.

Calvin Chan · Guest

Kanda may be a candidate for what I am after. But their PIC
programmer is currently under development and support only PIC18
series. Our devices have both PIC16 as well as PIC18.
https://www.kanda.com/productnews.php3

It looks to me that we are likely to implement our own. The
implementation involves using a MCU with 32K or 64K flash, eg.
atmega32 or atmega64. First to implement a hex file interpreter and
write the byte stream into its flash. Once this is done, the code
will be always ready to download to target by following the
corresponding ISP protocol.

Rgds

Calvin

On 17 Dec 2004 02:42:18 -0800, "matt@avisaro.com" <matt@avisaro.com>
wrote:

Byron A Jeff · Guest

In article <cqg4s0h4dbp9l9ooeg5gg6j539pndauvtr@4ax.com>,
Calvin Chan <calvin_chan@post1.com> wrote:
-Byron
-
-That means the service engineer onsite owns a copy of hex code which
-we do not really want.

It can be encrypted, so without a way to decrypt, it's not very useful.

- Also, the device is installed in odd area that
-bring a laptop and climb up long ladder is not a very nice way to do.

I didn't say laptop.

-
-Battery driven uploader is the ultimate goal.

So have one with a serial port. The idea is still sound. You can make it
somewhat more secure by using a different physical interface too.

The point is that you need a bootloader precisely because the PIC programming
interface is well known. A logic analyzer and access to the programmer gives
the holder access to the code. A bootloader allows you to define your interface
instead of using MChips standard interface.

BAJ

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