>>>>> "Andreas" == Andreas Färber <afaer...@suse.de> writes:
Andreas> Hi Uwe, Am 01.03.2015 um 14:25 schrieb Uwe Bonnes:
>> I am trying to get Openocd running with a Silab EFM32 Tiny Gecko
>> board I got some time ago. The board has some of the Silab demo
>> programm applied, probably using WFI in the Idle loop.
>>
>> Modifying Andreas Faerbers recently submitted xmc-2go.cfg accordingly
>> for the efm32, I got openocd started and I can connect to the
>> board. However reset is needed, as a "undefined debug reason 7 -
>> target needs reset" is displayed. Emitting "mon reset halt" however
>> gives "Polling target efm32.cpu failed, GDB will be halted. Polling
>> again in ..." in a loop. Using "reset_config none" lets me also
>> connect, with the same "undefined debug reason 7 - target needs
>> reset" message. However after "mon reset halt" the CPU is halted as
>> expected.
>>
>> So why use "reset_config srst_only srst_nogate" and not "reset_config
>> none"?
Andreas> The xmc-2go.cfg was a fairly recent submission; on an earlier
Andreas> xmc1000 config in that series Paul outlined for me what to
Andreas> check:
Andreas> 'I guess this is likely to have hardware reset routed properly,
Andreas> so please add "reset_config srst_only". If it's known the chip
Andreas> can talk over swd while the reset is held, reset_config
Andreas> srst_nogate should be added to the target config too.'
Andreas> http://openocd.zylin.com/#/c/2472/
Andreas> Unfortunately I don't have any efm32 board, and there doesn't
Andreas> seem to be any board config referencing efm32.cfg yet.
Okay, now I understand a little more. When the reset buttom is pressed,
neither of the configs I created connects to the EFM32. So it seems that SWD
doesn't work with reset asserted with the EFM32.
So my original question is changed to:
Why use "reset_config srst_only" and not "reset_config none"?
And another question comes to mind:
Why is "srst_nogate" a board configuration item and not a target item?
It is the target chip that refuses to work with SWD/JTAG under reset and
only in very rare cases a board issue, e.g. if there is an explicit external
gate blocking SWD in reset.
Thanks for your clarification!
--
Uwe Bonnes b...@elektron.ikp.physik.tu-darmstadt.de
Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
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