MCF548x Reference Manual, Rev. 3
8-18 Freescale Semiconductor

taken under the defined conditions. Breakpoint logic may be configured as one- or two-level triggers.

TDR[31–16] or XTDR[31–16] define second-level triggers, and bits 15–0 define first-level triggers.

TDR is accessible in supervisor mode as debug control register 0x07 using the WDEBUG instruction and

through the BDM port using the WDMREG command.

NOTE

The debug module has no hardware interlocks, so to prevent spurious

breakpoint triggers while the breakpoint registers are being loaded, disable

TDR and XTDR (by clearing TDR[29,13] and XTDR[29,13]) before

defining triggers.

A write to TDR clears the CSR trigger status bits, CSR[BSTAT].

When cleared, the data enable bits (EDxx) for both the second level and first level triggers disable data

breakpoints. When set, these bits enable the corresponding data breakpoint condition based on the size and

placement on the processors local data bus.

The address breakpoint for each trigger is enabled by setting the address enable bits (EAx); clearing all

three bits disables the corresponding breakpoint.

Table 8-12 describes TDR fields.

31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
Second Level Triggers
RTRC EBL
2
EDLW
2
EDWL
2
EDWU
2
EDLL
2
EDLM
2
EDUM
2
EDUU
2
DI
2
EAI
2
EAR
2
EAL
2
EPC
2
PCI
2
W
Reset0000000000000000
151413121110 9 8 7 6 543210
First Level Triggers
R0 0 EBL
1
EDLW
1
EDWL
1
EDWU
1
EDLL
1
EDLM
1
EDUM
1
EDUU
1
DI
1
EAI
1
EAR
1
EAL
1
EPC
1
PCI
1
W
Reset0000000000000000
Reg
Addr
CPU + 0x07

Figure 8-10. Trigger Definition Register (TDR)

Table 8-12. TDR Field Descriptions

Bits Name Description
31–30 TRC Trigger response control. Determines how the processor responds to a completed trigger
condition. The trigger response is always displayed on PSTDDATA.
00 Display on PSTDDATA only
01 Processor halt
10 Debug interrupt
11 Reserved
29 EBL2 Enable breakpoint. Global enable for the breakpoint trigger. Setting TDR[EBL] or XTDR[EBL]
enables a breakpoint trigger. If both TDL[EBL] and XTDL[EBL] are cleared, all breakpoints are
disabled.