Hi Andreas.
On Tue, 13 Jan 2015 16:47:58 +0100, Andreas Fritiofson wrote:
> On Tue, Jan 13, 2015 at 3:30 PM, Jens Bauer <jens-li...@gpio.dk> wrote:
>> Does any of this sound familiar to anyone or perhaps ring a bell ?
>
> Are you sure the chip isn't in reset? Measure the voltage on the
> reset pin. Is it connected anywhere?
I've pulled NRST up using a 4K7 resistor and it says 3.29V, which is what's
supplied to the VDD pins.
When connecting it to the JTAG-lock-pick Tiny 2 and when not connecting it; I
get the same result (pull-up is still enabled in both cases).
> During reset you can access SRAM but on some STM32 family (don't
> remember which) I have noticed that the flash is inaccessible. Sounds
> kind of similar, although I'd expect the GPIO registers would not be
> writable in reset.
It seems I have full access to all hardware registers and all SRAM.
Uhm... The Flexible Memory Controller isn't required for Flash-memory access,
is it ?
(FMC is disabled in the RCC->AHB3ENR register.
...
> BTW, did you resolve the STM32F407-DISCOVERY problem?
I had no real problems with the STM32F407-based Discovery board after writing
my 'program' routine like this:
proc unlockNow () {
stm32f2x unlock 0
mww 0x40023C08 0x08192A3B; mww 0x40023C08 0x4C5D6E7F; mww 0x40023C14
0x0fffaaed
}
proc flashNow {file_to_flash} {
init
sleep 200
reset halt
wait_halt
unlockNow ()
flash write_image erase "$file_to_flash"
# The following does not work (yet) for STM32F4 Discovery:
# flash write_image erase unlock "$file_to_flash"
reset run
sleep 10
shutdown
}
(The "stm32f2x unlock 0" is currently extraneous, but I expect that at some
point, the workaround will be removed).
-So it's possible to get OpenOCD to flash-program the board, but I think it'll
be necessary to modify the 'unlock' routine to include the FLASH_OPTCR
unlocking sequence + writing the value 0x0fffaaed.
(It's probably a good idea to check FLASH_SR, FLASH_CR and perhaps also
FLASH_OPTCR right after writing the new value).
I did notice that sometimes (on rare occasions), FLASH_OPTCR did go back to
0x00aaaae1; I have no idea why it did that.
However, my value seem to survive a complete power-off, so it's not changed
back after a reset or power-cycle.
Love
Jens
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