smc256af Numonyx, smc256af Datasheet - Page 48

• Manufacturer Part Number: smc256af
• Description: 32 Mbyte, 64 Mbyte, 128 Mbyte, 256 Mbyte And 512 Mbyte 3.3 V / 5 V Supply Compactflash? Card
• Manufacturer: Numonyx

CF-ATA registers
8.9
8.9.1
8.9.2
8.9.3
8.9.4
8.9.5
8.9.6
8.9.7
8.9.8
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Status & alternate status registers (address 1F7h [177h] &
3F6h [376h]; offsets 7 & Eh)
These registers return the card status when read by the host.
Reading the status register clears a pending interrupt. Reading the auxiliary status register
does not clear a pending interrupt.
The status register should be accessed in Byte mode; in Word mode it is recommended that
alternate status register is used. The status bits are described as follows
Bit 7 (BUSY)
The busy bit is set when only the card can access the command register and buffer. The
host is denied access. No other bits in this register are valid when this bit is set to ‘1’.
Bit 6 (RDY)
This bit indicates whether the device is capable of performing CompactFlash memory card
operations. This bit is cleared at power-up and remains cleared until the card is ready to
accept a command.
Bit 5 (DWF)
When set this bit indicates a write fault has occurred.
Bit 4 (DSC)
This bit is set when the card is ready.
Bit 3 (DRQ)
The data request is set when the card requires information be transferred either to or from
the host through the data register. The bit is cleared by the next command.
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. In case of read or write
access commands that end with an error, the address of the first sector with an error is in
the command block registers. This bit is cleared by the next command.
SMCxxxAF