User Manual

ATA Command Description

5-22 CompactFlash

5.1.28. Write Sector(s)—30H, 31H

Table 5-34. Write Sectors

Bit -> 7 6 5 4 3 2 1 0

Command (7) 30H or 31H

C/D/H (6) 1 LBA 1 Drive Head (LBA 27-24)

Cyl High (5) Cylinder High (LBA 23-16)

Cyl Low (4) Cylinder Low (LBA 15-8)

Sec Num (3) Sector Number (LBA 7-0)

Sec Cnt (2) Sector Count

Feature (1) X

This command writes from 1 to 256 sectors as specified in the Sector Count Register. A sector count of zero

requests 256 sectors. The transfer begins at the sector specified in the Sector Number Register. When this command

is accepted, the CompactFlash Memory Card sets BSY, then sets DRQ and clears BSY, then waits for the host to fill

the sector buffer with the data to be written. No interrupt is generated to start the first buffer fill operation. No data

should be transferred by the host until BSY has been cleared by the host.

For multiple sectors, after the first sector of data is in the buffer, BSY will be set and DRQ will be cleared. After the

next buffer is ready for data, BSY is cleared, DRQ is set and an interrupt is generated. When the final sector of data

is transferred, BSY is set and DRQ is cleared. It will remain in this state until the command is completed at which

time BSY is cleared and an interrupt is generated.

If an error occurs during a write of more than one sector, writing terminates at the sector where the error occurs. The

Command Block Registers contain the cylinder, head and sector number of the sector where the error occurred. The

host may then read the command block to determine what error has occurred, and on which sector.

5.1.29. Write Sector(s) without Erase—38H

Table 5-35. Write Sectors without Erase