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author | David Brownell <dbrownell@users.sourceforge.net> | 2009-11-05 11:31:32 -0800 |
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committer | David Brownell <dbrownell@users.sourceforge.net> | 2009-11-05 11:31:32 -0800 |
commit | afed39c0fe20bffcf0f289e59e80ab9d6bb40a91 (patch) | |
tree | 4eff38b57bd0d4497b20c63aff86d8ab41397295 /doc | |
parent | 98788d7a75b4321c96845a8fbf814f254a6cf153 (diff) | |
download | openocd+libswd-afed39c0fe20bffcf0f289e59e80ab9d6bb40a91.tar.gz openocd+libswd-afed39c0fe20bffcf0f289e59e80ab9d6bb40a91.tar.bz2 openocd+libswd-afed39c0fe20bffcf0f289e59e80ab9d6bb40a91.tar.xz openocd+libswd-afed39c0fe20bffcf0f289e59e80ab9d6bb40a91.zip |
User's Guide: TAP setup tweakage
Highlight that the "-expected-id" probably comes from vendor
documentation, and that it *should* be used where possible.
Don't use ircapture/irmask in examples, to help discourage
use of those params when they're not required. Explain a
bit better about why/when those params get used.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Diffstat (limited to 'doc')
-rw-r--r-- | doc/openocd.texi | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/doc/openocd.texi b/doc/openocd.texi index 2108f8e5..2ddcd041 100644 --- a/doc/openocd.texi +++ b/doc/openocd.texi @@ -1339,8 +1339,7 @@ The config file for the Atmel AT91SAM7X256 looks (in part) like this: @example -jtag newtap $_CHIPNAME cpu -irlen 4 -ircapture 0x1 -irmask 0xf \ - -expected-id $_CPUTAPID +jtag newtap $_CHIPNAME cpu -irlen 4 -expected-id $_CPUTAPID @end example A board with two such at91sam7 chips would be able @@ -2496,7 +2495,7 @@ requires explicit configuration of all TAP devices using A command like this would declare one tap and name it @code{chip1.cpu}: @example -jtag newtap chip1 cpu -irlen 7 -ircapture 0x01 -irmask 0x55 +jtag newtap chip1 cpu -irlen 4 -expected-id 0x3ba00477 @end example Each target configuration file lists the TAPs provided @@ -2641,13 +2640,21 @@ These codes are not required by all JTAG devices. ID code could appear (for example, multiple versions). Specify @var{number} as zero to suppress warnings about IDCODE values that were found but not included in the list. + +Provide this value if at all possible, since it lets OpenOCD +tell when the scan chain it sees isn't right. These values +are provided in vendors' chip documentation, usually a technical +reference manual. Sometimes you may need to probe the JTAG +hardware to find these values. +@xref{Autoprobing}. @item @code{-ircapture} @var{NUMBER} @*The bit pattern loaded by the TAP into the JTAG shift register on entry to the @sc{ircapture} state, such as 0x01. JTAG requires the two LSBs of this value to be 01. By default, @code{-ircapture} and @code{-irmask} are set -up to verify that two-bit value; but you may provide -additional bits, if you know them. +up to verify that two-bit value. You may provide +additional bits, if you know them, or indicate that +a TAP doesn't conform to the JTAG specification. @item @code{-irmask} @var{NUMBER} @*A mask used with @code{-ircapture} to verify that instruction scans work correctly. @@ -6149,12 +6156,13 @@ to execute before they take effect. @end deffn @c tms_sequence (short|long) -@c ... temporary, debug-only, probably gone before 0.2 ships +@c ... temporary, debug-only, other than USBprog bug workaround... @deffn Command {verify_ircapture} (@option{enable}|@option{disable}) Verify values captured during @sc{ircapture} and returned during IR scans. Default is enabled, but this can be overridden by @command{verify_jtag}. +This flag is ignored when validating JTAG chain configuration. @end deffn @deffn Command {verify_jtag} (@option{enable}|@option{disable}) |