|
From: Uwe B. <bo...@el...> - 2015-03-01 15:52:10
|
>>>>> "Paul" == Paul Fertser <fer...@gm...> writes:
Paul> On Sun, Mar 01, 2015 at 04:06:28PM +0100, Uwe Bonnes wrote:
>> So my original question is changed to:
>>
>> Why use "reset_config srst_only" and not "reset_config none"?
Paul> reset_config none is default. If the specific board has SRST
Paul> connected properly, it's usually more reliable to use hardware
Paul> reset (SRST) to reset the target CPU (and probably other
Paul> components), especially if the target doesn't support any good way
Paul> for software reset.
I have some F411 nucleo board that I run battery powered. The reset line and
some other lines between the stlink and the target go to none 5 volt
tolerant lines of the STLink cpu and draw substantial battery current when
the stlink is not USB powered. A nucleo config with "reset_config none" will
work with both the modified and unmodifies nucleo board, while "reset_config
srst_only" will work only for the unmodified board.
Another situation is with using the STLink from nucleo or discovery to go
off board to another CPU. "reset_config srst_only" as given with most
configs, will require another jumper wire, while "reset_config none" as
default doesn't need that wire.
In general, I think we catch more situations and we require less assumptions
with SWD and probably JTAG with "reset_config none". And the user can always
supersede with -c "reset_config srst_only" in the rare cases needed, like
remapped SWD/JTAG pins.
So I don't buy the "it's usually more reliable" argument :-)
Cheers
--
Uwe Bonnes bo...@el...
Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
|