Chapter 36 Nexus Development Interface (NDI)
MPC5602P Microcontroller Reference Manual, Rev. 4
Freescale Semiconductor
897
36.11.3 Debug External Resource Control Register (DBERC0)
The Debug External Resource Control Register (DBERC0) controls resource allocation when DBCR0
EDM
is set to ‘1’. DBERC0 provides a mechanism for the hardware debugger to share certain debug resources
with software. Individual resources are allocated based on the settings of DBERC0 when DBCR0
EDM
=1.
DBERC0 settings are ignored when DBCR0
EDM
=0.
Hardware-owned resources which generate debug events update DBSR and cause entry into debug mode,
while software-owned resources which generate debug events if DBCR0
IDM
=1, update DBSR and act as
if they occurred in internal debug mode, thus causing debug interrupts to occur if MSR
DE
=1. DBERC0 is
controlled via the OnCE port hardware, and is read-only to software.
Debug status bits in DBSR are set by software-owned debug events only while Internal Debug Mode is
enabled. When debug interrupts are enabled (MSR
DE
=1 DBCR0
IDM
=1 and DBCR0
EDM
=0, or MSR
DE
=1,
DBCR0
IDM
=1 and DBCR0
EDM
=1 and software is allocated resource(s) via DBERC0), a set bit in DBSR
which is software-owned other than MRR or VLES will cause a debug interrupt to be generated.
Debug status bits in DBSR are set by hardware-owned debug events only while External Debug Mode is
enabled (DBCR0
EDM
=1).
16
RET
Return Debug Event
Set to ‘1’ if a Return debug event occurred
17:20
—
Reserved
21
DEVT1
External Debug Event 1 Debug Event
Set to ‘1’ if a DEVT1 debug event occurred
22
DEVT2
External Debug Event 2 Debug Event
Set to ‘1’ if a DEVT2 debug event occurred
23:24
—
Reserved
25
CIRPT
Critical Interrupt Taken Debug Event
Set to ‘1’ if a Critical Interrupt Taken debug event occurred.
26
CRET
Critical Return Debug Event
Set to ‘1’ if a Critical Return debug event occurred
27
VLES
VLE Status
Set to ‘1’ if an ICMP, BRT, TRAP, RET, CRET, IAC, or DAC debug event occurred on a Power
Architecture technology VLE Instruction. Undefined for IRPT, CIRPT, DEVT[1,2], and UDE
events
28
—
Reserved
29:30
DAC_OFST
Data Address Compare Offset
Indicates offset-1 of saved DSRR0 value from the address of the load or store instruction
which took a DAC Debug exception, unless a simultaneous DSI error occurs, in which case
this field is set to 2‘b00 and DBSR
IDE
is set to ‘1’. Normally set to 2‘b00 by a non-DVC DAC.
A DVC DAC may set this field to any value.
31
—
Reserved
Table 36-6. DBSR Bit Definitions (continued)
Bit(s)
Name
Description