3.5.1. Debug request output wiring

When the trigger condition occurs, you can set the ETM7 to assert DBGRQ until DBGACK is observed under the control of bit 9 in the ETM control register.

Note

ARM7 processors take at least one cycle to respond to DBGRQ. This means that the ARM processor can execute a few instructions after the trigger condition is detected but before the system has stopped. Some debug tools can report an unrecognized breakpoint as a result.

It is recommended that you connect the DBGRQ output of the ETM7 to the DBGRQ input of the ARM processor. If this input is already in use, for example a DBGRQ input is present on the device, the DBGRQ signals can be ORed together as shown in Figure 3.11.

Figure 3.11. Combining DBGRQ inputs

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