5. External event breakpoints
5.1. Overview
ARM-JTAG-EW has the ability to halt the target CPU upon detecting an
external event like a current/voltage spike/drop, external input trigger,
external input pulse detection.
External Breakpoints Block Diagram is given on page 9.
External events can be defined with a simple C-like expression like this
(see page 9 for more information):
(3000<U_tg && U_tg<3600)
So when ARM-JTAG-EW detects that U
TG
>3000mV AND U
TG
<3600mV, it
will shift a request to the target CPU to halt.
Multiple inputs can be mixed into one event:
(3000<U_tg && U_tg<3600) || I_tgpwr>200
WARNING:
There is always some time between an actual event and the
corresponding action by ARM-JTAG-EW. Due to the limited sampling rate
of analogue signals, ARM-JTAG-EW cannot detect instantly changes on its
inputs. Also note that shifting the JTAG sequence for requesting a target
CPU halt also takes time, depending on the TCK frequency. Heavy USB
traffic can also influence the response time.
