Development Support
MPC561/MPC563 Reference Manual, Rev. 1.2
Freescale Semiconductor
23-19
23.2.3
Watchpoint Counters
There are two 16-bit watchpoint counters. Each counter is able to count one of the instruction watchpoints
or one of the load/store watchpoints. Both generate the corresponding breakpoint when they reach ZERO.
When working in the masked mode, the counters do not count watchpoints detected when MSR[RI] = 0.
See
Section 23.2.1.4, “Context Dependent Filter
.”
The counters value when counting watchpoints programmed on the actual instructions that alter the
counters, are not predictable. Reading values from the counters when they are active, must be
synchronized by inserting a sync instruction before the actual read is performed.
NOTE
When programmed to count instruction watchpoints, the last instruction
which decrements the counter to ZERO is treated like any other instruction
breakpoint in the sense that it is not executed and the machine branches to
the breakpoint exception routine BEFORE it executes this instruction. As a
side effect of this behavior, the value of the counter inside the breakpoint
exception routine equals ONE and not ZERO as might be expected.
When programmed to count load/store watchpoints, the last instruction which decrements the counter to
ZERO is treated like any other load/store breakpoint in the sense that it is executed and the machine
branches to the breakpoint exception routine AFTER it executes this instruction. Therefore, the value of
the counter inside the breakpoint exception routine equals ZERO.
23.2.3.1
Trap Enable Programming
The trap enable bits can be programmed by regular software (only if MSR[PR] = 0) using the mtspr
instruction or “on the fly” using the special development port interface. For more information refer to
section
Section 23.4.6.5, “Development Port Serial Communications — Trap Enable Mode
.”
The value used by the breakpoints generation logic is the bit wise OR of the software trap enable bits, (the
bits written using the mtspr) and the development port trap enable bits (the bits serially shifted using the
development port).
All bits, the software trap enable bits and the development port trap enable bits, can be read from ICTRL
and the LCTRL2 using mfspr. For the exact bits placement refer to
Section 23.6.10, “L-Bus Support
Section 23.6.10, “L-Bus Support Control Register 2
23.3
Development System Interface
When debugging an existing system, it is sometimes desirable to be able to do so without the need to insert
any changes in the existing system. In some cases it is not desired, or even impossible, to add load to the
lines connected to the existing system. The development system interface of the CPU supports such a
configuration.
The development system interface of the CPU uses a dedicated serial port (the development port) and,
therefore, does not need any of the regular system interfaces. Controlling the activity of the system from
the development port is done when the CPU is in the debug mode. The development port is a relatively
Summary of Contents for MPC561
Page 84: ...MPC561 MPC563 Reference Manual Rev 1 2 lxxxiv Freescale Semiconductor...
Page 144: ...Signal Descriptions MPC561 MPC563 Reference Manual Rev 1 2 2 46 Freescale Semiconductor...
Page 206: ...Central Processing Unit MPC561 MPC563 Reference Manual Rev 1 2 3 62 Freescale Semiconductor...
Page 302: ...Reset MPC561 MPC563 Reference Manual Rev 1 2 7 14 Freescale Semiconductor...
Page 854: ...Time Processor Unit 3 MPC561 MPC563 Reference Manual Rev 1 2 19 24 Freescale Semiconductor...
Page 968: ...Development Support MPC561 MPC563 Reference Manual Rev 1 2 23 54 Freescale Semiconductor...
Page 1144: ...Internal Memory Map MPC561 MPC563 Reference Manual Rev 1 2 B 34 Freescale Semiconductor...
Page 1212: ...TPU3 ROM Functions MPC561 MPC563 Reference Manual Rev 1 2 D 60 Freescale Semiconductor...
Page 1216: ...Memory Access Timing MPC561 MPC563 Reference Manual Rev 1 2 E 4 Freescale Semiconductor...