MPC555CME Freescale Semiconductor, MPC555CME Datasheet - Page 739

• Manufacturer Part Number: MPC555CME
• Description: KIT EVALUATION FOR MPC555
• Manufacturer: Freescale Semiconductor
• Type: Microcontrollerr

Specifications of MPC555CME

• Contents: Module Board, Installation Guide, Power Supply, Cable, Software and more
• Processor To Be Evaluated: MPC555
• Data Bus Width: 32 bit
• Interface Type: RS-232
• For Use With/related Products: MPC555
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

21.6 Software Monitor Debugger Support
21.6.1 Freeze Indication
21.7 Development Support Registers
MPC555
USER’S MANUAL
The sequence of the instructions used in the “fast download procedure” is the one il-
lustrated in
nitely until the “end download procedure” command is issued to the debug port.
Note that, the internal general purpose register 31 is used for temporary storage data
value. Before beginning the “fast download procedure” by the “start download proce-
dure command”, The value of the first memory block address, – 4, must be written to
the general purpose register 30.
To end a download procedure, an “end download procedure” command should be is-
sued to the debug port, and then, additional DATA transaction should be sent by the
development tool. This data word will NOT be placed into the system memory, but it is
needed to stop the procedure gracefully.
When in debug mode disable, a software monitor debugger can make use of all of the
development support features defined in the CPU. When debug mode is disabled all
events result in regular interrupt handling, i.e. the processor resumes execution in the
corresponding interrupt handler. The exception cause register (ECR) and the debug
enable register (DER) only influence the assertion and negation of the freeze signal.
The internal freeze signal is connected to all relevant internal modules. These modules
can be programmed to stop all operations in response to the assertion of the freeze
signal. In order to enable a software monitor debugger to broadcast the fact that the
debug software is now executed, it is possible to assert and negate the internal freeze
signal also when debug mode is disabled.
The assertion and negation of the freeze signal when in debug mode disable is con-
trolled by the exception cause register (ECR) and the debug enable register (DER) as
described in
program the relevant bits in the debug enable register (DER). In order to negate the
freeze line the software needs to read the exception cause register (ECR) in order to
clear it and perform an rfi instruction.
If the exception cause register (ECR) is not cleared before the rfi is performed the
freeze signal is not negated. Therefore it is possible to nest inside a software monitor
debugger without affecting the value of the freeze line although rfi may be performed
a few times. Only before the last rfi the software needs to clear the exception cause
register (ECR).
The above mechanism enables the software to accurately control the assertion and
the negation of the freeze signal.
Table 21-14
cessed with the mtspr and mfspr instructions.
/
MPC556
Figure 21-11
Figure
lists the registers used for development support. The registers are ac-
21-6. In order to assert the freeze signal the software needs to
with RX = r31 and RY = r30. This sequence is repeated infi-
DEVELOPMENT SUPPORT
Rev. 15 October 2000
MOTOROLA
21-43