Chapter 8 DMA Controller
8-9
During Single Address transfer, the DMA Destination Address Register (DMDARn) and DMA
Destination Address Increment Register (DMDAIRn) settings are ignored.
Table 8.3.2 Channel Register Setting Restrictions During Single Address Transfer
DMSARn[1:0]
Transfer Setting
Size
(DMCCRn.XFSZ)
DMSAIRn is “0” or
greater
DMSAIRn setting is a
negative value
DMSAIRn[1:0] DMCNTRn[1:0]
1 Byte
** **
** **
2 Bytes
*
0
*
1
*
0
*
0
4 Bytes
00
11
00
00
4 Words
8 Words
16 Words
32 Words
00 11
4/0/-4
00
8.3.7.2
Burst Transfer During Single Address Transfer
According to the SDRAM Controller and External Bus Controller specifications, the DMA
Controller cannot perform Burst transfer that spans across 32 word boundaries. Consequently, if
the address that starts DMA transfer is not a multiple of the transfer setting size (DMCCRn.XFSZ)
(is not aligned), transfer cannot be performed by any of the transfer sizes that were specified by a
Burst transfer. Therefore, the DMA Controller executes multiple Burst transactions of a transfer
size smaller than the specified transfer size. This division method changes according to the seting
of the Transfer Size Mode bit (DMCCRn.USEXFSZ) of the DMA Channel Control Register.
Figure 8.3.2 shows the Single Address Burst transfer status when the lower 7 bits of the
Transfer Start address are 0x54 and the transfer setting size (DMCCRn.XFSZ) is set to 4 words.
Panel (a) of this figure shows the situation when the Transfer Size Mode bit
(DMCCRn.USEXFSZ) is “0”. In this case, first a three word transfer is performed up to the
address aligned to the transfer setting size. Then, four word transfer specified by the transfer
setting size is repeated. This setting is normally used.
On the other hand, panel (b) shows when the Transfer Size Mode bit (DMCCRn.USEXFSWZ)
is “1”. in this case, transfer is repeated according to the transfer setting size. Three word transfer
and one word transfer is only performed consecutively without releasing bus ownership when
transfer spans across a 32 word boundary.
Содержание TMPR4925
Страница 1: ...64 Bit TX System RISC TX49 Family TMPR4925 Rev 3 0 ...
Страница 4: ......
Страница 15: ...Handling Precautions ...
Страница 16: ......
Страница 18: ...1 Using Toshiba Semiconductors Safely 1 2 ...
Страница 40: ...3 General Safety Precautions and Usage Considerations 3 18 ...
Страница 42: ...4 Precautions and Usage Considerations 4 2 ...
Страница 43: ...TMPR4925 ...
Страница 44: ......
Страница 54: ...Chapter 1 Features 1 8 ...
Страница 58: ...Chapter 2 Block Diagram 2 4 ...
Страница 88: ...Chapter 4 Address Mapping 4 12 ...
Страница 226: ...Chapter 8 DMA Controller 8 58 ...
Страница 260: ...Chapter 9 SDRAM Controller 9 34 ...
Страница 480: ...Chapter 15 Interrupt Controller 15 32 ...
Страница 554: ...Chapter 19 Real Time Clock RTC 19 8 ...
Страница 555: ...Chapter 20 Removed 20 1 20 Removed ...
Страница 556: ...Chapter 20 Removed 20 2 ...
Страница 564: ...Chapter 21 Extended EJTAG Interface 21 8 ...
Страница 580: ...Chapter 22 Electrical Characteristics 22 16 ...
Страница 586: ...Chapter 23 Pin Layout Package 23 6 23 2 Package Package Type Package Code 256 pin PBGA PBGA 4L P BGA256 2727 1 27A4 ...
Страница 588: ...Chapter 24 Usage Notes 24 2 ...
Страница 590: ...Appendix A TX49 H2 Core Supplement A 2 ...