ETM: add "etm trigger_debug" command

In conjunction with manual register setup, this lets the ETM trigger
cause entry to debug state.   It should make it easier to test and
bugfix the ETM code, by enabling non-trace usage and isolating bugs
specific to thef ETM support.  (One current issue being that trace
data collection using the ETB doesn't yet behave.)

For example, many ARM9 cores with an ETM should be able to implement
four more (simple) breakpoints and two more (simple) watchpoints than
the EmbeddedICE supports.  Or, they should be able to support complex
breakpoints, incorporating ETM sequencer, counters, and/or subroutine
entry/exit criteria int criteria used to trigger debug entry.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index efcf8f6..e122912 100644
--- a/NEWS
+++ b/NEWS
@@ -34,6 +34,7 @@ Target Layer:
 		- Exposed DWT registers like cycle counter
 	ETM, ETB
 		- "trigger_percent" command moved ETM --> ETB
+		- "etm trigger_debug" command added
 
 Flash Layer:
 	'flash bank' and 'nand device' take <bank_name> as first argument.