Jtag ram patcher chip?

[is0-mick]

Just came across your forum
I had a look at a bt vision a few months ago, but may have another play with it again now.

I was just thinking, it should be possible to create a chip that jtags the CPU, checks the bootloader version and applies the patch at the correct location. Then resumes execution.

The box could then be used stand alone without the need to be connected to a pc, and it would bypass the signature check.

It would be quite a neet solution i think.

Mick

[asgard]

it's already realised

http://www.t-hack.com/forum/index.php?topic=47.45

[mce2222]

... and it is a general solution that can be used for any smp863x based device

[is0-mick]

what compiler is used to compile the avr code?
I tried WinAVR but seem to get lots of errors (things not defined like PORTB5).

EDIT: Just noticed the makefile... DOH



RESET DETECTED
RESET DETECTED
BUSPROBE OK
CPUID: 00001000011000110000000000000001 (63000001)
Found SigmaDesigns SMP8634 Rev A CPU
CPU / PER. RESET OK
CPU HALT <CPU entered DBGMODE> OK
CLEAR WATCHDOG OK
UNKNOWN BL
CPU DBGMODE EXIT
RESET DETECTED
RESET DETECTED
RESET DETECTED
BOOT SIGPATCH

I could not get the programmer circuit posted to work either.. I found one that works here:

http://www.flightsim.com/howto/mind/avrisp.gif


Also any ideas how to find _RESET on the BT box?

Thanks
Mick

[is0-mick]

Ok got it working...

BOOT SIGPATCH
BUSPROBE OK
CPUID: 00001000011000110000000000000001 (63000001)
Found SigmaDesigns SMP8634 Rev A CPU
CPU / PER. RESET OK
CPU HALT <CPU entered DBGMODE> OK
CLEAR WATCHDOG OK
BT vision Version 1527 found
PATCH OK
CPU DBGMODE EXIT
RESET DETECTED


Just need to find the CPU _RESET...

Any ideas??

Cheers
Mick

[is0-mick]

OK

Think I've found RESET, there is a 4 pin connector just above the JTAG enable pins. The pin seems to toggle when I use the reset on the jtag connector, or reset using pwr+OK on the front of the box.


o 1
o 2
o 3
o 4  <--reset


o o <-- jtag enable connector
2 1

It didnt seem to reset when i did "Quit client"


Mick