MC9S12G FREESCALE [Freescale Semiconductor, Inc], MC9S12G Datasheet - Page 303

• Manufacturer Part Number: MC9S12G
• Description: Ignores external trigger. Performs one conversion sequence and stops.
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

match occurs when all data bus bits with corresponding mask bits set are equivalent. If all mask register
bits are clear, then a match is based on the address bus only, the data bus is ignored.
When matching on a difference, mask bits can be cleared to ignore bit positions. A match occurs when any
data bus bit with corresponding mask bit set is different. Clearing all mask bits, causes all bits to be ignored
and prevents a match because no difference can be detected. In this case address bus equivalence does not
cause a match.
8.4.2.2
Using the AB comparator pair for a range comparison, the data bus can also be used for qualification by
using the comparator A data 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. The SZE and SZ control bits are ignored in range mode. The comparator A TAG bit is used to tag
range comparisons. The comparator B TAG bit is 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. The comparator A BRK bit is used to for the AB range, the comparator B BRK bit is
ignored in range mode.
When configured for range comparisons and tagging, the ranges are accurate only to word boundaries.
8.4.2.2.1
In the Inside Range comparator mode, comparator pair A and B can be configured for range comparisons.
This configuration 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 is valid only if the aligned address
is inside the range.
8.4.2.2.2
In the Outside Range comparator mode, comparator pair A and B can be configured for range comparisons.
A single match condition on either of the comparators is recognized as valid. An aligned word access
which straddles the range boundary is valid only if the aligned address is outside the range.
Outside range mode in combination with tagging can be used to detect if the opcode fetches are from an
unexpected range. In forced match mode the outside range match would typically be activated at any
interrupt vector fetch or register access. This can be avoided by setting the upper range limit to $3FFFF or
lower range limit to $00000 respectively.
Freescale Semiconductor
This document is valid for the S12G96 and the S12G128 device. All information related to other devices is preliminary.
NDB
Range Comparisons
0
0
1
1
Inside Range (CompA_Addr ≤ address ≤ CompB_Addr)
Outside Range (address < CompA_Addr or address > CompB_Addr)
DBGADHM[n] /
DBGADLM[n]
0
1
0
1
Table 8-34. NDB and MASK bit dependency
MC9S12G Family Reference Manual, Rev.1.01
Compare data bus bit. Match on equivalence.
Compare data bus bit. Match on difference.
Do not compare data bus bit.
Do not compare data bus bit.
Comment
S12S Debug Module (S12SDBG)
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