Product manual

CompactFlash Memory Card Product Manual Preliminary

5.5.9 Status & Alternate Status Registers (Address

1F7[177]&3F6[376];

Offsets 7 & Eh)

These registers return the CompactFlash Memory

Card status when read by the host. Reading the

Status register does clear a pending interrupt

while reading the Auxiliary Status register does

not. The meaning of the status bits are described as

follows:

D7 D6 D5 D4 D3 D2 D1 D0

BUSY RDY DWF DSC DRQ CORR 0 ERR

Bit 7 (BUSY) The busy bit is set when the CompactFlash Memory Card has access to the command buffer and registers

and the host is locked out from accessing the command register and buffer. No other bits in this register are

valid when this bit is set to a 1.

Bit 6 (RDY) RDY indicates whether the device is capable of performing CompactFlash Memory Card operations. This bit

is cleared at power up and remains cleared until the CompactFlash Card is ready to accept a command.

Bit 5 (DWF) This bit, if set, indicates a write fault has occurred.

Bit 4 (DSC) This bit is set when the CompactFlash Memory Card is ready.

Bit 3 (DRQ) The Data Request is set when the CompactFlash Memory Card requires that information be transferred either

to or from the host through the Data register.

Bit 2 (CORR) This bit is set when a Correctable data error has been encountered and the data has been corrected. This

condition does not terminate a multi-sector read operation.

Bit 1 (IDX) This bit is always set to 0.

Bit 0 (ERR) This bit is set when the previous command has ended in some type of error. The bits in the Error register

contain additional information describing the error.