On Fri, Nov 8, 2013 at 10:04 PM, Brandon Warhurst <[email protected]>wrote:
> I forgot to mention the following:
> 1) I tried changing the ftdi_layout_init to 0x0008 0x006B. This produces
> the result I was originally expecting, however, the delay doesn't seem to
> have any effect.
>
I guess that's because the physical reset lines are initialized low when
the adapter is initialized, and they are driven high again as soon as
OpenOCD deasserts srst and trst during startup.
> On Nov 8, 2013, at 4:00 PM, Brandon Warhurst wrote:
>
> > I was checking my FTDI adapter reset lines, and found out that they
> don't seem to toggle properly. My JTAG adapter can really only push-pull
> the reset lines, so I set both resets up as push-pull types (I don't have
> any
> > output enables on the lines). The adapter is wired so that I have the
> GPIOxL lines (1,2,3, 0 is rtck) available to become a reset. Currently I
> have selected lines 1 & 2, so I've used the following lines:
> >
> > ftdi_layout_init 0x0068 0x006B
> > ftdi_layout_signal nTRST -ndata 0x0020
> > ftdi_layout_signal nSRST -ndata 0x0040
> >
> > This is after fooling around with the lines for a while and producing no
> results at all, meaning, on a scope, all I would see is the lines being
> driven high. When I turned on debug, I only ever see reset getting called
> once, with arguments of 0,0 for ntrst and nsrst. I would have expected
> that reset would get called again after delaying for "width" milliseconds
> to change the reset line state (i.e. I would expect the line to start high,
> given my init parameters, then go low during the reset period, then be
> pulled high again after the reset period). Is this not what is supposed to
> happen? I am probably misunderstanding how OpenOCD reset is supposed to
> work, but that is certainly the result I would like to produce.
>
The reset lines are not used at all (except for the initial deactivation
you've been seeing) unless you say you want to use it. You'll want to play
with the reset_config command. Moreover, reset is never pulled without some
request (such as the reset command or by the target code). It's
specifically not asserted automatically during init. Different targets may
handle this differently. You've not given any details on your setup.
/Andreas
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