Development Support
MPC561/MPC563 Reference Manual, Rev. 1.2
23-4
Freescale Semiconductor
23.1.1.3
Queue Flush Information Special Case
There is one special case when although queue flush information is expected on the VF pins, (according
to the last value on the VF pins), regular instruction type information is reported. The only instruction type
information that can appear in this case is VF = 111, branch (direct or indirect) NOT taken. Since the
maximum queue flushes possible is five, it is easy to identify this special case.
23.1.2
Program Trace when in Debug Mode
When entering debug mode an interrupt/exception taken is reported on the VF pins, (VF = 100) and a cycle
marked with the program trace cycle is made visible externally.
When the CPU is in debug mode, the VF pins equal ‘000’ and the VFLS pins equal ‘11’. For more
information on debug mode refer to
Section 23.3, “Development System Interface
If VSYNC is asserted/negated while the CPU is in debug mode, this information is reported as the first VF
pins report when the CPU returns to regular mode. If VSYNC was not changed while in debug mode. the
first VF pins report will be of an indirect branch taken (VF = 101), suitable for the rfi instruction that is
being issued. In both cases the first instruction fetch after debug mode is marked with the program trace
cycle attribute and therefore is visible externally.
23.1.3
Sequential Instructions Marked as Indirect Branch
There are cases when non-branch (sequential) instructions may effect the machine in a manner similar to
indirect branch instructions. These instructions include rfi, mtmsr, isync and mtspr to CMPA-F, ICTRL,
ECR and DER.
These instructions are marked by the CPU as indirect branch instructions (VF = 101) and the following
instruction address is marked with the same program trace cycle attribute as if it were an indirect branch
target. Therefore, when one of these special instructions is detected in the CPU, the address of the
following instruction is visible externally. In this way the reconstructing software is able to evaluate
correctly the effect of these instructions.
23.1.4
External Hardware
When program trace is needed, the external hardware needs to sample the status pins (VF and VFLS) each
clock cycle and the address of all cycles marked with the program trace cycle attribute.
Table 23-3. VFLS Pin Encodings
VFLS[0:1]
History Buffer Flush Information
00
0 instructions flushed from history queue
01
1 instruction flushed from history queue
10
2 instructions flushed from history queue
11
Used for debug mode indication (FREEZE). Program trace
external hardware should ignore this setting.
Summary of Contents for MPC561
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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...
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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...