What is Next for the AL Priority?

[FJR1300]

Nope, you're way above my pay grade in component level pc board theory!

I take things apart all the time, definitely respect like minded tinkerers and modders.

[radargeek]

yeah, there's a whopper. 8 megabyte of flash. and i would agree about chip functions. the usb capable chip is probably also doing the AesDecode() that enables everyone's firmware to be unique, it's also capable of secure aes booting, running code from ram (not that i've noticed any), and other fun things. there's an ISCP header on the left (i say that, knowing full well that PIC doesn't use ISCP) if you want to try bricking yours. there's also a green led on either side of the board that flashes nicely (as in, not too brightly).

Actually PIC does use ICSP. And the higher end ones support JTAG as well. But it's more likely than not that AL uses the on-chip protection features to make it next to impossible to read the firmware off the chip itself. They probably use the ICSP header to flash the bootloader, and possibly the initial firmware, onto the chips during assembly.

still, i am left wondering, if there's only 256 + 128 = 384k of flash, why are our U0000000.bin files 460K?

Maybe there's data tables or loadable code that gets put into the serial flash?

And I also can't see the thread – if pulling a brand new ALP apart can't get you some respect in the secret forums where other people pull things apart, I just don't know what will. Possibly putting them back together, but I can't find the top anymore.

LOL... hope you can find the top! Just keep participating here and you'll be promoted soon enough.

[orwellophile]

Actually PIC does use ICSP. And the higher end ones support JTAG as well. But it's more likely than not that AL uses the on-chip protection features to make it next to impossible to read the firmware off the chip itself. They probably use the ICSP header to flash the bootloader, and possibly the initial firmware, onto the chips during assembly.

I didn't make a note of what firmware mine came with, but they would (at a minimum) be programming in the serial number (and associated decryption key) at final assembly, otherwise the sticker wouldn't match.

I confess I was not aware any PIC used ICSP, (consulting wikipedia), ahh... my error is one of AVR arrogance, the pic of course support "In Circuit System Programming", but not necessarily with the same pins, protocol (or voltages) that any of my many AVR programmers would be used to.

It was the 6 pin AVR ICSP header, I traced a couple of lines, and kind of assumed. Lets do it properly:




Hmmm... pin 4 is not connected. pin 4 would be required for the programmer to send data regardless, assuming standard pinouts for pic or avr.

(shrug) as you say, there'd be nothing good to get. even the flash memory chip has a secure 256 byte area. speaking of which, if it stored the lookup tables in flash, they'd be mighty slow to use. maybe the extra space in the .BIN is for a copy of the "upgrade loader" or somesuch.

Maybe there's data tables or loadable code that gets put into the serial flash?LOL... hope you can find the top! Just keep participating here and you'll be promoted soon enough.

Oh, *facepalm*, maybe the ISCP header is to send data *TO* something. Can't imagine what, serial port would be most obvious – but don't need that many pins. some kind of LCD display perhaps. mystery.

[radargeek]

Chances are only the ALP engineers who developed the thing knows what the on-board headers are used for. Probably for the initial flash of the bootloader/serial/encryption keys and maybe for QA testing as well (test all the functions of the board before it's shipped). It may also be used for diagnostic purposes if a defective unit is sent back for repair/refurbishment. Even if it is an ICSP header, it's possible and probable that AL uses their own pinout rather than the standard one PIC programmers use. It could just be a diagnostic serial port to allow a diagnostic computer to talk to the processors on the board.

It's possible that the chips have bootloaders flashed on them even before they're installed on the board (I think Microchip offers this as a service for volume customers). They would still need serial #/encryption key info added if it's unique to each device. There's probably a computer at the factory programmed to do this, each time a board/CPU goes out it connects to the header, gives it a serial # and key, and prints the S/N stickers to put on the outside.

There's another header on the board, near the USB port. It's 6 pads inline but without holes. It looks much like a standard PIC ICSP header. And it even appears that pin 3 is ground and pin 6 is unused.