Chapter 8 DMA Controller
8-14
Figure 8.3.3 Dual Address Burst Transfer (DMCCRn.USEXFSZ
=
1)
Figure 8.3.4 shows Dual Address Burst transfer when the Transfer Size Mode bit
(DMCCRn.USEXFSZ) is set to “0”, the lower 8 bits of the Transfer Start address for the transfer
source are set to 0xA8, the lower 8 bits of the Transfer Start address for the transfer destination are
set to (a) 0x28/(b) 0x30, and the Transfer Setting Size (DMCCRn.XFSZ) is set to 8 double words.
Panel (a) of this figure shows when the address offset is equivalent. In this case, first transfer of
three double words is performed up to the address that is aligned with the transfer setting size.
Then, transfer of eight double words that is specified by the transfer setting size is repeated.
On the other hand, panel (b) show when the address offset is not equivalent. In this case, first
only data up to the address that is aligned with the transfer setting size is read to the on-chip FIFO.
Then, data is written up to the address that is aligned with the transfer setting size as long as data
remains in the on-chip FIFO. Efficiency decreases since the transfer size is divided. Also, since
data may remain in the on-chip FIFO, Burst transfer of a Dual Address that uses the on-chip FIFO
simultaneously with another channel cannot be performed.
Using the Burst Inhibit bit makes it possible to mix Burst transfer with 8-Double-Word Single
transfer. This in turn makes it possible to perform Burst access only for memory access during
DMA transfer with external I/O devices that cannot perform Burst transfer.
When the Source Burst Inhibit bit (DMCCRn.SBINH) is set, data read from the Source Address
to the on-chip FIFO is divided into multiple 8-byte Single Read transfers, then transfer is
executed.
a0
a8
b0
b8
c8
d0
d8
c0
e8
f0
f8
e0
00
08
10
18
28
30
38
20
63
0
20
28
30
38
48
50
58
40
68
70
78
60
80
88
90
98
a8
b0
b8
a0
63
0
Source Address
FIFO (8 Double Words)
Destination Address
Summary of Contents for TX49 TMPR4937
Page 1: ...64 Bit TX System RISC TX49 Family TMPR4937 Rev 2 0 ...
Page 4: ......
Page 13: ...Table of Contents ix TMPR4937 Revision History 1 ...
Page 14: ...Table of Contents x ...
Page 15: ...Handling Precautions ...
Page 16: ......
Page 18: ...1 Using Toshiba Semiconductors Safely 1 2 ...
Page 40: ...3 General Safety Precautions and Usage Considerations 3 18 ...
Page 42: ...4 Precautions and Usage Considerations 4 2 ...
Page 43: ...TMPR4937 2005 3 Rev 2 0 ...
Page 44: ......
Page 52: ...Chapter 1 Overview and Features 1 6 ...
Page 156: ...Chapter 7 External Bus Controller 7 56 ...
Page 491: ...Chapter 16 Removed 16 1 16 Removed ...
Page 492: ...Chapter 16 Removed 16 2 ...
Page 493: ...Chapter 17 Removed 17 1 17 Removed ...
Page 494: ...Chapter 17 Removed 17 2 ...
Page 495: ...Chapter 18 Removed 18 1 18 Removed ...
Page 496: ...Chapter 18 Removed 18 2 ...
Page 497: ...Chapter 19 Removed 19 1 19 Removed ...
Page 498: ...Chapter 19 Removed 19 2 ...
Page 506: ...Chapter 20 Extended EJTAG Interface 20 8 ...
Page 530: ...Chapter 22 Pinout and Package Information 22 10 ...
Page 542: ...Chapter 24 Parts Number when Ordering 24 2 ...