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MC9S12XD256CAL Datasheet, PDF (715/1348 Pages) Freescale Semiconductor, Inc – This specification describes the function of the clocks and reset generator (CRG). | |||
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Chapter 19 S12X Debug (S12XDBGV2) Module
19.4.2.2 Exact Address Comparator Match (Comparators B and D)
Comparators B and D feature SZ and SZE control bits. If SZE is clear, then the comparator address match
qualiï¬cation functions the same as for comparators A and C.
If the SZE bit is set the access size (word or byte) is compared with the SZ bit value such that only the
speciï¬ed type of access causes a match. Thus, if conï¬gured for a byte access of a particular address, a word
access covering the same address does not lead to match.
Table 19-37. Comparator Access Size Considerations
Comparator
Address
SZE SZ8
Condition For Valid Match
Comparators
A and C
Comparators
B and D
Comparators
B and D
ADDR[n]
ADDR[n]
ADDR[n]
-
-
0
X
1
0
Word and byte accesses of ADDR[n]1
MOVB #$BYTE ADDR[n]
MOVW #$WORD ADDR[n]
Word and byte accesses of ADDR[n]1
MOVB #$BYTE ADDR[n]
MOVW #$WORD ADDR[n]
Word accesses of ADDR[n]1
MOVW #$WORD ADDR[n]
Comparators
B and D
ADDR[n]
1
1
Byte accesses of ADDR[n]
MOVB #$BYTE ADDR[n]
1 A word access of ADDR[n-1] also accesses ADDR[n] but does not generate a match.
The comparator address register must contain the exact address used in the code.
19.4.2.3 Range Comparisons
When using the AB comparator pair for a range comparison, the data bus can also be used for qualiï¬cation
by using the comparator A data and data mask registers. Furthermore the DBGACTL RW and RWE bits
can be used to qualify the range comparison on either a read or a write access. The corresponding
DBGBCTL bits are ignored. Similarly when using the CD comparator pair for a range comparison, the
data bus can also be used for qualiï¬cation by using the comparator C data and data mask registers.
Furthermore the DBGCCTL RW and RWE bits can be used to qualify the range comparison on either a
read or a write access if tagging is not selected. The corresponding DBGDCTL bits are ignored. The SZE
and SZ control bits are ignored in range mode. The comparator A and C TAG bits are used to tag range
comparisons for the AB and CD ranges respectively. The comparator B and D TAG bits are ignored in
range modes. In order for a range comparison using comparators A and B, both COMPEA and COMPEB
must be set; to disable range comparisons both must be cleared. Similarly for a range CD comparison, both
COMPEC and COMPED must be set. If a range mode is selected SRCA and SRCB must select the same
source (S12X or XGATE). Similarly SRCC and SRCD must select the same source. When conï¬gured for
range comparisons and tagging, the ranges are accurate only to word boundaries.
19.4.2.3.1 Inside Range (CompAC_Addr ⤠Address ⤠CompBD_Addr)
In the inside range comparator mode, either comparator pair A and B or comparator pair C and D can be
conï¬gured for range comparisons. This conï¬guration depends upon the control register (DBGC2). The
match condition requires that a valid match for both comparators happens on the same bus cycle. A match
condition on only one comparator is not valid. An aligned word access which straddles the range boundary
will cause a trigger only if the aligned address is inside the range.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
717
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