Re: [OpenOCD-user] srst with swd

[Richard B. <r...@ra...>]

That worked.  Thanks Spencer.  No, we didn't get an error about an invalid
command...

On Wed, Oct 15, 2014 at 11:00 AM, Spencer Oliver <sp...@sp...>
wrote:

> Richard,
>
> On 15 October 2014 14:48, Richard Bryan <r...@ra...> wrote:
> > Is there a configuration to force openocd to hold srst low when using
> SWD as
> > the transport?
> >
> > We're using openocd to program an Atmel SAMD20E using swd over a Segger
> > Jlink.  We're having trouble getting openocd to actually hold srst low.
> We
> > can program and  debug the device normally just fine, but this is only
> > hotplugging the device via the SWCLK/SWIO lines.
> >
> > Hotplugging fails obviously when we try to use the swd pins on our chip
> for
> > GPIO (they're multiplexed with a pair of buttons).  When multiplexing
> those
> > pins for GPIO, the only way to reflash the chip is to reset it using srst
> > and then perform swd transactions before the on-board program has a
> chance
> > to configure those pins as gpio.  We're unable to configure openocd to do
> > this though.
> >
> > We use the following board config:
> >
> >
> > transport select swd
> > source [find interface/cmsis-dap.cfg]
> >
> > # chip name
> > set CHIPNAME at91samd20e14
> >
> > source [find target/at91samdXX.cfg]
> >
> > init
> > reset
> >
> >
> > Along with the standard jlink.cfg for our Segger Jlink.
> >
> > We've also tried adding these config lines before init:
> >
> > cortex_m reset_config srst
> > cortex_m reset_config srst_nogate
> > cortex_m reset_config connect_assert_srst
> >
>
> Does this not complain about an invalid cmd, as it should ?
>
> > ...with the same result.
> >
> > Also, interestingly enough we see this debug output when running with -d
> > flag:
> >
> >
> > Debug: 366 67 cortex_m.c:1111 cortex_m_deassert_reset(): target->state:
> > reset
> > Debug: 367 119 jlink.c:671 jlink_reset(): trst: 0, srst: 0
> > Debug: 368 119 core.c:644 swd_add_reset(): SRST line released
> >
> >
> > But the srst line is not actually driven low as verified with an
> > oscilloscope.
> >
> > Is there something we're missing from our config?  We're using the
> lastest
> > master head (1ea25b85b) btw.
> >
>
> simply try
> reset_config srst_only srst_nogate connect_assert_srst
>
> Cheers
> Spen
>



-- 
Richard A Bryan
r...@ra...

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