David Brownell <david-b@pacbell.net>:
Minor updates to the text about reset configuration: - Mention a new point that it interacts with JTAG routers; - Talk about a "user" config file not a "system" one; - Remove text from the "reset_config" description; instead, cross-reference the more extensive text earlier. git-svn-id: svn://svn.berlios.de/openocd/trunk@2243 b42882b7-edfa-0310-969c-e2dbd0fdcd60
This commit is contained in:
parent
1ac220df71
commit
cc9488008a
|
@ -1911,6 +1911,7 @@ configuration. This can also be quite confusing.
|
|||
Resets also interact with @var{reset-init} event handlers,
|
||||
which do things like setting up clocks and DRAM, and
|
||||
JTAG clock rates. (@xref{JTAG Speed}.)
|
||||
They can also interact with JTAG routers.
|
||||
Please see the various board files for examples.
|
||||
|
||||
@quotation Note
|
||||
|
@ -1919,11 +1920,12 @@ Reset configuration touches several things at once.
|
|||
Normally the board configuration file
|
||||
should define it and assume that the JTAG adapter supports
|
||||
everything that's wired up to the board's JTAG connector.
|
||||
|
||||
However, the target configuration file could also make note
|
||||
of something the silicon vendor has done inside the chip,
|
||||
which will be true for most (or all) boards using that chip.
|
||||
And when the JTAG adapter doesn't support everything, the
|
||||
system configuration file will need to override parts of
|
||||
user configuration file will need to override parts of
|
||||
the reset configuration provided by other files.
|
||||
@end quotation
|
||||
|
||||
|
@ -1967,6 +1969,7 @@ and @command{reset init} commands; after @command{reset init} a
|
|||
board-specific script might do things like setting up DRAM.
|
||||
(@xref{Reset Command}.)
|
||||
|
||||
@anchor{SRST and TRST Issues}
|
||||
@section SRST and TRST Issues
|
||||
|
||||
Because SRST and TRST are hardware signals, they can have a
|
||||
|
@ -1979,9 +1982,11 @@ common issues are:
|
|||
SRST or TRST to the JTAG connector. Some JTAG adapters don't
|
||||
support such signals even if they are wired up.
|
||||
Use the @command{reset_config} @var{signals} options to say
|
||||
when one of those signals is not connected.
|
||||
when either of those signals is not connected.
|
||||
When SRST is not available, your code might not be able to rely
|
||||
on controllers having been fully reset during code startup.
|
||||
Missing TRST is not a problem, since JTAG level resets can
|
||||
be triggered using with TMS signaling.
|
||||
|
||||
@item @emph{Signals shorted} ... Sometimes a chip, board, or
|
||||
adapter will connect SRST to TRST, instead of keeping them separate.
|
||||
|
@ -2051,17 +2056,14 @@ This command tells OpenOCD the reset configuration
|
|||
of your combination of JTAG board and target in target
|
||||
configuration scripts.
|
||||
|
||||
If you have an interface that does not support SRST and
|
||||
TRST(unlikely), then you may be able to work around that
|
||||
problem by using a reset_config command to override any
|
||||
settings in the target configuration script.
|
||||
|
||||
SRST and TRST has a fairly well understood definition and
|
||||
behaviour in the JTAG specification, but vendors take
|
||||
liberties to achieve various more or less clearly understood
|
||||
goals. Sometimes documentation is available, other times it
|
||||
is not. OpenOCD has the reset_config command to allow OpenOCD
|
||||
to deal with the various common cases.
|
||||
Information earlier in this section describes the kind of problems
|
||||
the command is intended to address (@pxref{SRST and TRST Issues}).
|
||||
As a rule this command belongs only in board config files,
|
||||
describing issues like @emph{board doesn't connect TRST};
|
||||
or in user config files, addressing limitations derived
|
||||
from a particular combination of interface and board.
|
||||
(An unlikely example would be using a TRST-only adapter
|
||||
with a board that only wires up SRST.)
|
||||
|
||||
The @var{mode_flag} options can be specified in any order, but only one
|
||||
of each type -- @var{signals}, @var{combination}, @var{trst_type},
|
||||
|
|
Loading…
Reference in New Issue