Datasheet

Read Multiple
This command is supported for backward compatibility. If R/W Multiple commands have been enabled by a previous
valid Set Multiple command, the Read Multiple command is identical to Read Sectors operation except that several
sectors are transferred as a block to the Host without intervening Host handshaking. The number of sectors to
transfer as a block is referred to as the block count. The block count is established using the Set Multiple command.
Although the Set Multiple, and R/W Multiple commands are supported, the only valid block count is one.
If Read Multiple has not been enabled, the ABRT (Aborted Command) bit is set in the Error register and the
command terminates.
Read Multiple Command Issued by Host
Task File Register 7 6 5 4 3 2 1 0
COMMAND C4h
DRIVE/HEAD nu L nu D H[3:0] or LBA[27:24] of the starting sector/LBA
CYLINDER HI Cylinder[15:8] or LBA[23:16] of the first sector/LBA to transfer
CYLINDER LOW Cylinder[7:0] or LBA[15:8] of the first sector/LBA to transfer
SECTOR START Sector[7:0] or LBA[7:0] of the first sector/LBA to transfer
SECTOR COUNT The number of sectors/logical blocks to transfer
FEATURES nu
Command Block specified upon completion/termination of Read Multiple command (C4h)
Task File Register 7 6 5 4 3 2 1 0
BSY DRDY DWF DSC DRQ CORR IDX ERR
STATUS 0 1 0 1 V V 0 V
DRIVE/HEAD na na na na H[3:0] or LBA[27:24] last good sector transferred
CYLINDER HI Cylinder[15:8] or LBA[23:16] of the last good sector transferred
CYLINDER LOW Cylinder[7:0] or LBA[15:8] of the last good sector transferred
SECTOR Sector[7:0] or LBA[7:0] of the last good sector transferred
SECTOR COUNT The number of sectors that were not transferred if an unrecoverable error occurred. Zero otherwise.
BBK UNC MC IDNF MCR ABRT TK0NF AMNF
ERROR 0 V 0 V 0 0 0 0