Development Support
MPC561/MPC563 Reference Manual, Rev. 1.2
23-14
Freescale Semiconductor
When working in the masked mode, all internal breakpoints detected when MSR[RI] = 0 are lost.
Watchpoints detected in this case are not counted by the debug counters. Watchpoints detected are always
reported on the external pins, regardless of the value of MSR[RI].
Out of reset, the CPU is in masked mode. Programming the CPU to be in non-masked mode is done by
Register 2.” The BRKNOMSK bit controls all internal breakpoints (I-breakpoints and L-breakpoints).
23.2.1.5
Ignore First Match
In order to facilitate the debugger utilities “continue” and “go from x”, the ignore first match option is
supported for instruction breakpoints. When an instruction breakpoint is first enabled (as a result of the
first write to the instruction support control register or as a result of the assertion of MSR[RI] when
operating in the masked mode), the first instruction will not cause an instruction breakpoint if the ignore
first match (IFM) bit in the instruction support control register (ICTRL) is set (used for “continue”).
When the IFM bit is clear, every matched instruction can cause an instruction breakpoint (used for “go
from x”). This bit is set by the software and cleared by the hardware after the first instruction breakpoint
match is ignored. Load/store breakpoints and all counter generated breakpoints (instruction and load/store)
are not affected by this mode.
23.2.1.6
Generating Six Compare Types
Using the four compare types mentioned above (equal, not equal, greater than, less than) it is possible to
generate also two more compare types: greater than or equal and less than or equal.
Generating the greater than or equal compare type can be done by using the greater than compare
type and programming the comparator to the needed value minus 1.
Generating the less than or equal compare type can be done by using the less than compare type
and programming the comparator to the needed value plus 1.
This method does not work for the following boundary cases:
Less than or equal of the largest unsigned number (1111...1)
Greater than or equal of the smallest unsigned number (0000...0)
Less than or equal of the maximum positive number when in signed mode (0111...1)
Greater than or equal of the maximum negative number when in signed mode (1000...)
These boundary cases need no special support because they all mean ‘a(chǎn)lways true’ and can be programmed
23.2.2
Instruction Support
There are four instruction address comparators A,B,C, and D. Each is 30 bits long, generating two output
signals: equal and less than. These signals are used to generate one of the following four events: equal, not
equal, greater than, less than.