Microcontroller User's Manual

MOTOROLA Chapter 29. Debug Support 29-27
Background Debug Mode (BDM)
Command Sequence:
Figure 29-24. 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.
29.5.3.3.5 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’