System Development and Debugging
MPC885 PowerQUICC Family Reference Manual, Rev. 2
53-32
Freescale Semiconductor
interrupt is shifted out. The next transmission, after all error status is reported to the port, should be a new
instruction, trap enable, or command.
The interrupt occurred encoding indicates that the core encountered an interrupt during the execution of
the previous instruction in debug mode. Interrupts may occur as the result of instruction execution (such
as unimplemented opcode or arithmetic error), because of a memory access fault, or from an unmasked
external interrupt. When an interrupt occurs the development port ignores the command, instruction, or
data shifted in while the interrupt encoding was shifting out. The next transmission to the port should be a
new instruction, trap enable, or debug port command. Finally, the null encoding indicates that no data was
transferred from the core to the development port shift register.
53.3.2.5.3
Fast Download Procedure
The fast download procedure downloads a block of data from the debug tool into the system memory by
repeating the sequence of transactions shown in
Figure 53-12
from the development tool to the debug port
for the number of data words to be downloaded.
Figure 53-12. Download Procedure Code Example
In this example, RX = r31 and RY = r30. The sequence is repeated until the end download procedure
command is issued to the debug port. GPR31 temporarily stores the data value. Before issuing the start
download procedure command, the value of the first memory block address -4 must be written into
GPR30. To end the download, an end download procedure command should be issued to the debug port
and an additional data transaction should be sent by the development tool. This data word is not placed
into system memory, but it is needed to stop the procedure.
For large blocks of data this sequence may take a long time to complete. The fast download procedure can
reduce this time by eliminating the need to transfer instructions in the loop to the debug port. The only
transactions needed are those that transfer the data to be placed in the system memory.
Figure 53-13
shows
the time benefit of the fast download procedure.
INIT:
Save RX, RY
RY <- Memory Block address- 4
•••
repeat:
mfspr
RX, DPDR
DATA word to be moved to memory
stwu
RX, 0x4(RY)
until here
•••
Restore RX,RY
Summary of Contents for PowerQUICC MPC870
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Page 118: ...MPC885 Overview MPC885 PowerQUICC Family Reference Manual Rev 2 1 20 Freescale Semiconductor ...
Page 158: ...The MPC8xx Core MPC885 PowerQUICC Family Reference Manual Rev 2 3 18 Freescale Semiconductor ...
Page 288: ...MPC885 PowerQUICC Family Reference Manual Rev 2 III 4 Freescale Semiconductor ...
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Page 1090: ...UTOPIA Interface MPC885 PowerQUICC Family Reference Manual Rev 2 43 8 Freescale Semiconductor ...
Page 1312: ...Byte Ordering MPC885 PowerQUICC Family Reference Manual Rev 2 A 8 Freescale Semiconductor ...
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Page 1370: ...MPC880 MPC885 PowerQUICC Family Reference Manual Rev 2 E 4 Freescale Semiconductor ...
Page 1386: ...Revision History MPC885 PowerQUICC Family Reference Manual Rev 2 I 2 Freescale Semiconductor ...