Section 7 DMA Controller (DMAC)
Rev. 3.00 Mar. 14, 2006 Page 175 of 804
REJ09B0104-0300
Figure 7.29 shows a flowchart of the XY conversion.
: User operation
: DMAC operation
Start
Set address and transfer count
Set repeat transfer mode
Set DTE bit to 1
Receives transfer request
Transfers data
Decrements transfer count
and repeat size
Enable repeat escape interrupt
Set transfer source a 4
Initializes transfer source address
Generates repeat size end
interrupt request
Transfer count = 0?
Repeat size = 0?
End
No
No
Yes
Yes
(Longword transfer)
Figure 7.20 XY Conversion Flowchart Using Offset Addition in Repeat Transfer Mode
(3)
Offset Subtraction
When setting the negative value in DOFR, the offset value must be 2's complement. The 2's
complement is obtained by the following formula.
2's complement of offset = 1 + ~offset (~: bit inversion)
Example:
2's complement of H'0001FFFF
= H'FF H'00000001
= H'FFFE0001
The value of 2's complement can be obtained by the NEG.L instruction.
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Содержание H8SX series
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