SH7721 datasheet(497/1524 Pages) RENESAS

497 / 1524 page

Section 10

Direct Memory Access Controller (DMAC)

Rev. 3.00 Jan. 18, 2008 Page 435 of 1458

REJ09B0033-0300

(1)

Address Modes

(a)

Dual Address Mode

In dual address mode, both the transfer source and destination are accessed by an address. The

source and destination can be located externally or internally.

DMA transfer requires two bus cycles because data is read from the transfer source in a data read

cycle and written to the transfer destination in a data write cycle. At this time, transfer data is

temporarily stored in the DMAC. In the transfer between external memories as shown in figure

10.5, data is read to the DMAC from one external memory in a data read cycle, and then that data

is written to the other external memory in a write cycle.

Data buffer

Memory

Transfer source

module

Transfer destination

module

Memory

Transfer source

module

Transfer destination

module

SAR

DAR

Data buffer

SAR

DAR

The SAR value is an address, data is read from the transfer source module,

and the data is temporarily stored in the DMAC.

First bus cycle

Second bus cycle

The DAR value is an address and the value stored in the data buffer in the

DMAC is written to the transfer destination module.

DMAC

Figure 10.5

Data Flow of Dual Address Mode

Auto request, external request, and on-chip peripheral module request are available for the transfer

request. DACK can be output in read cycle or write cycle in dual address mode. The channel

control register (CHCR) can specify whether the DACK is output in read cycle or write cycle.

SH7721 Datasheet(PDF) 497 Page - Renesas Technology Corp

SH7721 Datasheet(HTML) 497 Page - Renesas Technology Corp

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL