User Manual

CompactFlash Memory Card Interface Description

3-22 CompactFlash

RRdy/-Bsy This bit is used to determine the internal state of the Rdy/-Bsy signal. This bit may be used to determine the

state of the Ready/-Busy as this pin has been reallocated for use as Interrupt Request on an I/O card. When

written, this bit acts as a mask for writing the corresponding bit CRdy/-Bsy.

RWProt This bit is always zero (0) since the CompactFlash Memory Card does not have a Write Protect switch. When

written, this bit acts as a mask for writing the corresponding bit CWProt.

MRdy/-Bsy This bit acts as a mask for writing the corresponding bit CRdy/-Bsy.

MWProt This bit when written acts as a mask for writing the corresponding bit CWProt.

Table 3-20. Pin Replacement Changed Bit/Mask Bit Values

Written by Host

Initial Value of

“C” Bit “M” Bit

Final

“C” Bit

Comments

0 X 0 0 Unchanged

1 X 0 1 Unchanged

X 0 1 0 Cleared by Host

X 1 1 1 Set by Host

3.4.5. Socket and Copy Register (Address 206h in Attribute Memory

This register contains additional configuration information. This register is always written by the system before

writing the card’s Configuration Index Register.

Table 3-21. Socket and Copy Register Organization

Operation D7 D6 D5 D4 D3 D2 D1 D0

Read Reserved 0 0 Drive # 0 0 0 0

Write 0 0 0 Drive # (0) X X X X

Reserved This bit is reserved for future standardization. This bit must be set to zero (0) by the software when the

Drive # This bit indicates the drive number of the card if twin card configuration is supported.

X The socket number is ignored by the CompactFlash Memory Card.

3.5. I/O Transfer Function

The following sections provide valuable information for the I/O Transfer function.