Updates for "reset_config":
- revert to previous default: don't talk JTAG during SRST - add "srst_nogates" flag, the converse of "srst_gates_jtag" - with no args, display the current configuration And update the User's Guide text with bullet lists to be a bit more clear. git-svn-id: svn://svn.berlios.de/openocd/trunk@2818 b42882b7-edfa-0310-969c-e2dbd0fdcd60
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@@ -2099,7 +2099,7 @@ nTRST (active-low JTAG TAP reset) before starting new JTAG operations.
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@end deffn
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@deffn {Command} reset_config mode_flag ...
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This command tells OpenOCD the reset configuration
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This command displays or modifies the reset configuration
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of your combination of JTAG board and target in target
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configuration scripts.
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@@ -2113,7 +2113,9 @@ from a particular combination of interface and board.
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with a board that only wires up SRST.)
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The @var{mode_flag} options can be specified in any order, but only one
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of each type -- @var{signals}, @var{combination}, @var{trst_type},
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of each type -- @var{signals}, @var{combination},
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@var{gates},
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@var{trst_type},
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and @var{srst_type} -- may be specified at a time.
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If you don't provide a new value for a given type, its previous
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value (perhaps the default) is unchanged.
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@@ -2121,6 +2123,8 @@ For example, this means that you don't need to say anything at all about
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TRST just to declare that if the JTAG adapter should want to drive SRST,
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it must explicitly be driven high (@option{srst_push_pull}).
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@itemize
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@item
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@var{signals} can specify which of the reset signals are connected.
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For example, If the JTAG interface provides SRST, but the board doesn't
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connect that signal properly, then OpenOCD can't use it.
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@@ -2128,10 +2132,11 @@ Possible values are @option{none} (the default), @option{trst_only},
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@option{srst_only} and @option{trst_and_srst}.
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@quotation Tip
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If your board provides SRST or TRST through the JTAG connector,
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If your board provides SRST and/or TRST through the JTAG connector,
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you must declare that or else those signals will not be used.
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@end quotation
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@item
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The @var{combination} is an optional value specifying broken reset
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signal implementations.
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The default behaviour if no option given is @option{separate},
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@@ -2144,26 +2149,37 @@ haven't seen hardware with such a bug, and can be worked around).
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@option{combined} implies both @option{srst_pulls_trst} and
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@option{trst_pulls_srst}.
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@option{srst_gates_jtag} indicates that asserting SRST gates the
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@item
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The @var{gates} tokens control flags that describe some cases where
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JTAG may be unvailable during reset.
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@option{srst_gates_jtag} (default)
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indicates that asserting SRST gates the
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JTAG clock. This means that no communication can happen on JTAG
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while SRST is asserted.
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Its converse is @option{srst_nogate}, indicating that JTAG commands
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can safely be issued while SRST is active.
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@end itemize
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The optional @var{trst_type} and @var{srst_type} parameters allow the
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driver mode of each reset line to be specified. These values only affect
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JTAG interfaces with support for different driver modes, like the Amontec
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JTAGkey and JTAGAccelerator. Also, they are necessarily ignored if the
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JTAGkey and JTAG Accelerator. Also, they are necessarily ignored if the
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relevant signal (TRST or SRST) is not connected.
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@itemize
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@item
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Possible @var{trst_type} driver modes for the test reset signal (TRST)
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are @option{trst_push_pull} (default) and @option{trst_open_drain}.
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are the default @option{trst_push_pull}, and @option{trst_open_drain}.
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Most boards connect this signal to a pulldown, so the JTAG TAPs
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never leave reset unless they are hooked up to a JTAG adapter.
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@item
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Possible @var{srst_type} driver modes for the system reset signal (SRST)
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are the default @option{srst_open_drain}, and @option{srst_push_pull}.
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Most boards connect this signal to a pullup, and allow the
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signal to be pulled low by various events including system
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powerup and pressing a reset button.
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@end itemize
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@end deffn
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