Customers Performing Own Upgrades. How Hard Can It Be?

[pedja089]

MikroE have nice little hid bootloader.
http://www.mikroe.com/img/developmen...der_window.jpg
It would be nice to have open source bootloader like that in PBP.

[Ioannis]

Hmm, if you send a hex file to your customer, how hard is to copy the circuit and use the hex on a new project, without you knowing it?

I prefer to keep my hex files really secret and away from any customer. Except if they have paid for it, and they own it.

Ioannis

[pedja089]

If loader is open source you can easily add encryption. Then you send encrypted file to customer, application send encrypted data to pic(prevent someone to try find encryption in exe file, or to tap communication). Also you could use every 4th byte, load dummy bytes in encrypted file, write file from bottom to top, etc. So hex should be pretty safe...
Searching forum I found this http://www.etc.ugal.ro/cchiculita/so...bootloader.htm, and it should be good starting point for pic firmware. App for PC shouldn't be problematic, read byte from file then send it to HID or serial port, easily to do in VB6...
But I'm not still sure how to use loader with PBP, how to remap interrupt vectors, etc...
Only thing is that I don't have enough time to try it. I thing it should be doable...
EDIT:
If someone really wants your hex, then he'll just send one or two mcu from your device to company like this http://itresearch.weebly.com/services.html, and copy your board.

[timmers]

Thanks for your comments. The security aspect is concerning and I haven't decided yet on how to protect my hex files.

I think the next step is to connect my data reader to the RX TX lines and examine the sequence for Microchip's bootloader and a HID based system.

[towlerg]

Not sure thats the best way to go about it. The USB enumeration process is very complex and mainly boilerplate (ie. unrelated to your situation). The volume of traffic can be quite overwhelming, even with a pukka USB analyser. Its probably easier to understand by looking at the code on the PC and on the PIC in tandem. One simple rule is that the device (PIC) will never send data unless requested by the host (PC). There are many software only tools that will display HID host/device transactions (just the data not the overhead).

George