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found out why str912 reset halt failed. 

git-svn-id: svn://svn.berlios.de/openocd/trunk@688 b42882b7-edfa-0310-969c-e2dbd0fdcd60
This commit is contained in:
oharboe 2008-05-26 12:12:03 +00:00
parent e0d6a125c4
commit c45984f93e
1 changed files with 18 additions and 1 deletions
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19
src/jtag/bitbang.c
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@ -37,7 +37,24 @@
bitbang_interface_t *bitbang_interface;
/* should the clock be high or low in idle? */
/* DANGER!!!! clock absolutely *MUST* be 0 in idle or reset won't work!
*
* Set this to 1 and str912 reset halt will fail.
*
* If someone can submit a patch with an explanation it will be greatly
* appreciated, but as far as I can tell (ØH) DCLK is generated upon
* clk=0 in TAP_RTI. Good luck deducing that from the ARM documentation!
* The ARM documentation uses the term "DCLK is asserted while in the TAP_RTI
* state". With hardware there is no such thing as *while* in a state. There
* are only edges. So clk => 0 is in fact a very subtle state transition that
* happens *while* in the TAP_RTI state. "#&¤"#¤&"#&"#&
*
* For "reset halt" the last thing that happens before srst is asserted
* is that the breakpoint is set up. If DCLK is not wiggled one last
* time before the reset, then the breakpoint is not set up and
* "reset halt" will fail to halt.
*
*/
#define CLOCK_IDLE() 0
int bitbang_execute_queue(void);