SMC032BFY6 datasheet(67/91 Pages) STMICROELECTRONICS

67 / 91 page

SMCxxxBF

CF-ATA command description

67/91

10.10

Read DMA (C8h)

This command uses Multi-Word DMA mode to read from 1 to 256 sectors as specified in the

Sector Count register. If the sector count is set to ‘0’, 256 sectors will be read by issuing a

Read DMA command.

Data transfer begins at the sector specified in the Sector Number Register. When the Read

DMA command is issued, the CompactFlash Card asserts BSY, and transfers all or part of

the sector data in the buffer. The Card can then set DRQ and clear BSY, although it is not

required.

The Card asserts DMARQ when data are available to be transferred. The host then reads

the 512*sector-count Bytes of data from the Card using DMA protocol. When DMARQ is

asserted, the host asserts -DMACK to notify it is ready to transfer data, and asserts -IORD

once for each 16 bit Word to be transferred.

Interrupts are not generated for each sector transfer, but when all sectors have been

transferred or when an error occurred during the operation.

An Abort error is returned by the Card when a Read DMA command is sent by the host and

the 8-bit transfer mode has been enabled by the Set Features command.

Table 60 defines the Read DMA command Byte sequence.

Table 60.

Read DMA

Bit

5432

Command (7)

C8h

C/D/H (6)

LBA

Drive

Head (LBA 27-24)

Cyl High (5)

Cylinder High (LBA 23-16)

Cyl Low (4)

Cylinder Low (LBA 15-8)

Sect Num (3)

Sector Number (LBA 7-0)

Sect Cnt (2)

Sector Count

Feature (1)

SMC032BFY6 データシート(PDF) 67 Page - STMicroelectronics

SMC032BFY6 データシート(HTML) 67 Page - STMicroelectronics

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

データシートダウンロード