Background Debug Mode (BDM)
MCF548x Reference Manual, Rev. 3
Freescale Semiconductor 8-39
Command Sequence:
Figure 8-30. WRITE Command Sequence
Operand Data This two-operand instruction requires a longword absolute address that specifies
a location to which the data operand is to be written. Byte data is sent as a 16-bit
word, justified in the LSB; 16- and 32-bit operands are sent as 16 and 32 bits,
respectively.
Result Data Command complete status is indicated by returning 0xFFFF (with S cleared)
when the register write is complete. A value of 0x0001 (with S set) is returned if
a bus error occurs.
8.5.3.3.5 Dump Memory Block (DUMP)
DUMP is used with the READ command to access large blocks of memory. An initial READ is executed to
set up the starting address of the block and to retrieve the first result. If an initial READ is not executed
before the first DUMP, an illegal command response is returned. The DUMP command retrieves subsequent
operands. The initial address is incremented by the operand size (1, 2, or 4) and saved in a temporary
register. Subsequent DUMP commands use this address, perform the memory read, increment it by the
current operand size, and store the updated address in the temporary register.
XXX
’NOT READY’
WRITE (LONG)
???
MS ADDR
’NOT READY’
LS ADDR
’NOT READY’
WRITE
MEMORY
LOCATION
NEXT CMD
’CMD COMPLETE’
MS DATA
’NOT READY’
NEXT CMD
’NOT READY’
XXX
BERR
XXX
’NOT READY’
WRITE (B/W)
???
MS ADDR
’NOT READY’
LS ADDR
’NOT READY’
WRITE
MEMORY
LOCATION
NEXT CMD
’CMD COMPLETE’
DATA
’NOT READY’
NEXT CMD
’NOT READY’
XXX
BERR
LS DATA
’NOT READY’