In-circuit flash reading?

[Niclas Carlsson]

Hi!

I have an embedded controller devboard and a piece of consumer
electronics with some flash memory containing buggy code. I would like
to hook up the flash memory (without removing it) to the adress/data
lines of the devboard and in this way non-intrusively read out the
contents of the flash memory.

Could it work?

I suppose I might have to keep to uC on the flash pcb resetted (or in
standby?) to keep it from interfering?

Oh, and I would still have to think of a way of piggybacking my wires
on a PSOP. Any clues on that one? I'm trying to think of something that
would be easier/faster than removing the PSOP, reusable and cheap. =)

Cheers,

Nicke

 

[Chester]

The address bus of many CPUs are outputs only. Even if that kind of CPU is
in reset mode, outputs remain outputs. You'll have to check the CPU
datasheets of your piece of consumer electronics to know if the reset mode
allows access to its address/data bus from external devices. But a DMA mode
would be more appropriate.

Chester

"Niclas Carlsson" <sorry@nospam.here> a écrit dans le message de
news:Xns9500EA14A4D2Fvgodbfslassff@212.50.131.130...

Hi!

I have an embedded controller devboard and a piece of consumer
electronics with some flash memory containing buggy code. I would like
to hook up the flash memory (without removing it) to the adress/data
lines of the devboard and in this way non-intrusively read out the
contents of the flash memory.

Could it work?

I suppose I might have to keep to uC on the flash pcb resetted (or in
standby?) to keep it from interfering?

Oh, and I would still have to think of a way of piggybacking my wires
on a PSOP. Any clues on that one? I'm trying to think of something that
would be easier/faster than removing the PSOP, reusable and cheap. =)

Cheers,

Nicke

 

[Niclas Carlsson]

Hi!

"Chester" <mchester@directlan.net> wrote in
news:1JNwc.9755$yp6.518120@wagner.videotron.net:

The address bus of many CPUs are outputs only. Even if that kind of
CPU is in reset mode, outputs remain outputs. You'll have to check the
CPU datasheets of your piece of consumer electronics to know if the
reset mode allows access to its address/data bus from external
devices. But a DMA mode would be more appropriate.

Good point, thanks.

Nicke