dsp56800e Freescale Semiconductor, Inc, dsp56800e Datasheet - Page 319

• Manufacturer Part Number: dsp56800e
• Description: 16-bit Digital Signal Controller Core
• Manufacturer: Freescale Semiconductor, Inc

11.4.2
It is not necessary, however, to place the core in the Debug processing state to initialize the module. An
alternative technique is to first setup the desired Enhanced OnCE resources and then to enable these
resources. This can either be done through the JTAG port or through Core access via setup routines located
in an application, typically executed in the Normal processing state.
The Enhanced OnCE module also has the capability to generate interrupt requests in response to difference
debug events, each with its own dedicated interrupt vectors in the DSP56800E interrupt vector table. The
Enhanced OnCE exception trap is available to the user so that when a debug event is detected, an interrupt
can be generated and the program can initiate the appropriate handler routine. This allows the core to
perform many different actions in response to Debug events without halting the core. Instead, the event is
serviced by executing a dedicated interrupt service routine.
Freescale SemiconductorJTAG and Enhanced On-Chip Emulation (Enhanced OnCE)
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Execution of the DEBUGHLT instruction while the EOnCE is powered up
Step Counter expires while configured for debug request
Trace Buffer is full and configured for debug request
Breakpoint Unit Triggers occurs when programed for debug request
Debugging and the Other Processing States
Care must be taken when the core is in the Stop processing states. In this
state, all core clocks are disabled and it is not possible to access the
Enhanced OnCE module. The JTAG interface provides the means of
polling the device status (sampled in the capture-IR state). The core JTAG
TAP will bring the core out of Stop or Wait modes when
DEBUG_REQUEST is decoded in the TAP IR. A small amount of
additional power above the minimum possible will be expended by the
core TAP logic if the core TAP is utilized during Stop mode.
NOTE:
Enhanced OnCE and the Processing States
11-7