Chapter 36 Nexus Development Interface (NDI)
MPC5602P Microcontroller Reference Manual, Rev. 4
886
Freescale Semiconductor
provides bit definitions for Debug Control Register 0.
Table 36-2. DBCR0 Bit Definitions
Bit(s)
Name
Description
0
EDM
External Debug Mode. This bit is read-only by software.
0 – External debug mode disabled. Internal debug events not mapped into external debug
events.
1 – External debug mode enabled. Hardware-owned events will not cause the CPU to vector to
interrupt code. Software is not permitted to write to debug registers {DBCRx, DBSR, DBCNT,
IAC1–4, DAC1–2} unless permitted by settings in DBERC0.
When external debug mode is enabled, hardware-owned resources in debug registers are not
affected by processor reset
p_reset_b
. This allows the debugger to set up hardware debug
events which remain active across a processor reset.
Programming Notes:
It is recommended that debug status bits in the Debug Status Register be cleared before
disabling external debug mode to avoid any internal imprecise debug interrupts.
Software may use this bit to determine if external debug has control over the debug registers.
The hardware debugger must set the EDM bit to ‘1’ before other bits in this register (and other
debug registers) may be altered. On the initial setting of this bit to ‘1’, all other bits are
unchanged. This bit is only writable through the OnCE port.
1
IDM
Internal Debug Mode
0 – Debug exceptions are disabled. Debug events do not affect DBSR unless EDM is set.
1 – Debug exceptions are enabled. Enabled debug events will update the DBSR. If MSR
DE
=1,
the occurrence of a debug event, or the recording of an earlier debug event in the Debug Status
Register when MSR
DE
was cleared, will cause a Debug interrupt.
2:3
RST
Reset Control
00 – No function
01 – Reserved
10 –
p_resetout_b
pin asserted by Debug Reset Control. Allows external device to initiate
processor reset.
11 – Reserved
4
ICMP
Instruction Complete Debug Event Enable
0 – ICMP debug events are disabled
1 – ICMP debug events are enabled
5
BRT
Branch Taken Debug Event Enable
0 – BRT debug events are disabled
1 – BRT debug events are enabled
6
IRPT
Interrupt Taken Debug Event Enable
0 – IRPT debug events are disabled
1 – IRPT debug events are enabled
7
TRAP
Trap Taken Debug Event Enable
0 – TRAP debug events are disabled
1 – TRAP debug events are enabled
8
IAC1
Instruction Address Compare 1 Debug Event Enable
0 – IAC1 debug events are disabled
1 – IAC1 debug events are enabled