Specifications

4.13 Status register

CS1FX– = 1 DA2 = 1

CS3FX– = 0 DA1 = 1

Mode = Read Only DA0 = 1

PC-AT I/O port address: 1F7

This register contains either the drive status or the controller status. It is

updated at the completion of each command. If the host reads this

The bits in the Status register are defined below:

Bit 7 6 5 4 3 2 1 0

Name BSY DRDY DWF DSC DRQ CORR IDX ERR

BSY is the busy bit. It is set to 1 whenever the drive has access to the

command block. When it is set to 1:

• No other bits are valid.

• The host is locked out of reading shared registers; the Status

The BSY bit is set to 1 under the following circumstances:

• At the assertion of the RESET– signal on the interface

• At the assertion of the SRST bit in the Device Control register

• Immediately upon host write to the Command register

DRDY is the drive ready indicator bit. This bit is set to 0 at power up and

remains set at 0 until the drive is ready to accept a command.

DWF is the drive write fault bit. When there is a write fault error, this

bit is set to 1 and is not changed until the Status register is read

by the host, at which time the bit again indicates the current write

fault status.

DSC is the drive seek complete bit. It is set to 1 when the disc drive

is not seeking.

ATA Interface Reference Manual, Rev. C 21