MPC555
/
MPC556
DEVELOPMENT SUPPORT
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
21-23
Figure 21-5 Functional Diagram of MPC555
/
MPC556 Debug Mode Support
The development port provides a full duplex serial interface for communications be-
tween the internal development support logic of the CPU and an external development
tool. The development port can operate in two working modes: the trap enable mode
and the debug mode.
The trap enable mode is used in order to shift into the CPU internal development sup-
port logic the following control signals:
1. Instruction trap enable bits, used for on the fly programming of the instruction
breakpoint
2. Load/store trap enable bits, used for on the fly programming of the load/store
breakpoint
3. Non-maskable breakpoint, used to assert the non-maskable external break-
point
4. Maskable breakpoint, used to assert the maskable external breakpoint
5. VSYNC, used to assert and negate VSYNC
32
Development Port
Development Port
32
35
ECR
DER
CPU Core
DPIR
DPDR
9
TECR
Control Logic
Shift Register
DSDO
VFLS,
FRZ
EXT
BUS
SIU/
EBI
BKPT, TE,
VSYNC
DSDI
DSCK
Development
Support
Logic
Port
Internal
Bus
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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