Microcontroller User's Manual

MOTOROLA Chapter 29. Debug Support 29-25
Background Debug Mode (BDM)
Command/Result Formats:
Command Sequence:
Figure 29-22. READ Command Sequence
Operand Data The only operand is the longword address of the requested location.
Result Data Word results return 16 bits of data; longword results return 32. Bytes
are returned in the LSB of a word result; the upper byte is undefined.
0x0001 (S = 1) is returned if a bus error occurs.
15 12 11 8 7 4 3 0
Byte Command 0x1 0x9 0x0 0x0
A[31:16]
A[15:0]
Result XXXXXXXX D[7:0]
Word Command 0x1 0x9 0x4 0x0
A[31:16]
A[15:0]
Result D[15:0]
Longword Command 0x1 0x9 0x8 0x0
A[31:16]
A[15:0]
Result D[31:16]
D[15:0]
Figure 29-21. READ Command/Result Formats
XXX
’NOT READY’
READ (LONG)
???
MS ADDR
’NOT READY’
LS ADDR
’NOT READY’
NEXT CMD
’NOT READY’
NEXT CMD
LS RESULT
READ
MEMORY
LOCATION
XXX
BERR
XXX
MS RESULT
XXX
’NOT READY’
READ (B/W)
???
MS ADDR
’NOT READY’
LS ADDR
’NOT READY’
NEXT CMD
’NOT READY’
READ
MEMORY
LOCATION
XXX
BERR
NEXT CMD
RESULT