Datasheet

Chapter 16 Debug Module (DBGV1)
MC9S12E128 Data Sheet, Rev. 1.07
Freescale Semiconductor 487
16.3.2.7 Debug Control Register 2 (DBGC2)
Figure 16-13. Debug Control Register 2 (DBGC2)
Table 16-13. Comparator C Compares
PAGSEL EXTCMP Compare High-Byte Compare
x0 No compare DBGCCH[7:0] = AB[15:8]
x1 EXTCMP[5:0] = XAB[21:16] DBGCCH[7:0] = XAB[15:14],AB[13:8]
76543210
R
BKABEN
1
1
When BKABEN is set (BKP mode), all bits in DBGC2 are available. When BKABEN is cleared and DBG is used in DBG mode,
bits FULL and TAGAB have no meaning.
FULL BDM TAGAB BKCEN
2
2
These bits can be used in BKP mode and DBG mode (when capture mode is not set in LOOP1) to provide a third breakpoint.
TAGC
2
RWCEN
2
RWC
2
W
Reset 0 0 0 00000
Table 16-14. DBGC2 Field Descriptions
Field Description
7
BKABEN
Breakpoint Using Comparator A and B Enable — This bit enables the breakpoint capability using comparator
A and B, when set (BKP mode) the DBGEN bit in DBGC1 cannot be set.
0 Breakpoint module off
1 Breakpoint module on
6
FULL
Full Breakpoint Mode Enable — This bit controls whether the breakpoint module is in dual mode or full mode.
In full mode, comparator A is used to match address and comparator B is used to match data. See
Section 16.4.1.2, “Full Breakpoint Mode,” for more details.
0 Dual address mode enabled
1 Full breakpoint mode enabled
5
BDM
Background Debug Mode Enable — This bit determines if the breakpoint causes the system to enter
background debug mode (BDM) or initiate a software interrupt (SWI).
0 Go to software interrupt on a break request
1 Go to BDM on a break request
4
TAGAB
Comparator A/B Tag Select — This bit controls whether the breakpoint will cause a break on the next instruction
boundary (force) or on a match that will be an executable opcode (tagged). Non-executed opcodes cannot cause
a tagged breakpoint.
0 On match, break at the next instruction boundary (force)
1 On match, break if/when the instruction is about to be executed (tagged)
3
BKCEN
Breakpoint Comparator C Enable Bit — This bit enables the breakpoint capability using comparator C.
0 Comparator C disabled for breakpoint
1 Comparator C enabled for breakpoint
Note: This bit will be cleared automatically when the DBG module is armed in loop1 mode.
2
TAGC
Comparator C Tag Select — This bit controls whether the breakpoint will cause a break on the next instruction
boundary (force) or on a match that will be an executable opcode (tagged). Non-executed opcodes cannot cause
a tagged breakpoint.
0 On match, break at the next instruction boundary (force)
1 On match, break if/when the instruction is about to be executed (tagged)