Motorola MCF5281 ユーザーズマニュアル

MOTOROLA

Chapter 29.  Debug Support  

29-29

Command Sequence:

Operand Data:

None

Result Data:

Requested data is returned as either a word or longword. Byte data is 
returned in the least-significant byte of a word result. Word results 
return 16 bits of significant data; longword results return 32 bits. A 
value of 0x0001 (with S set) is returned if a bus error occurs.

A 

FILL

 command is used with the 

WRITE

 command to access large blocks of memory. An

initial 

WRITE

 is executed to set up the starting address of the block and to supply the first

operand. The 

FILL

 command writes subsequent operands. The initial address is incremented

by the operand size (1, 2, or 4) and saved in a temporary register after the memory write.
Subsequent 

FILL

 commands use this address, perform the write, increment it by the current

operand size, and store the updated address in the temporary register.

If an initial 

WRITE

 is not executed preceding the first 

FILL

 command, the illegal command

response is returned.

The 

FILL

 command does not check for a valid address—

FILL

 is

a valid command only when preceded by another 

FILL

, a 

NOP

,

or a 

WRITE

 command. Otherwise, an illegal command response

is returned. The 

NOP

 command can be used for intercommand

padding without corrupting the address pointer. 

XXX

’NOT READY’

DUMP (B/W)

???

XXX

’ILLEGAL’

NEXT CMD

’NOT READY’

NEXT CMD

’NOT READY’

READ 

MEMORY

LOCATION

XXX

BERR

NEXT CMD

RESULT

XXX

’NOT READY’

DUMP (LONG)

???

XXX

’ILLEGAL’

NEXT CMD

’NOT READY’

NEXT CMD

’NOT READY’

READ 

MEMORY

LOCATION

XXX

BERR

NEXT CMD

MS RESULT

NEXT CMD

LS RESULT