Datasheet

5−5
5.2 ExCA Interface Status Register
The ExCA interface status register provides information on the current status of the PC Card interface. An X in the
default bit value indicates that the value of the bit after reset depends on the state of the PC Card interface. See
Table 5−3 for a complete description of the register contents.
Bit 7 6 5 4 3 2 1 0
Default 0 0 X X X X X X
Register: ExCA interface status
Offset: CardBus socket address + 801h; ExCA offset 01h
Type: Read-only
Default: 00XX XXXXb
Table 5−3. ExCA Interface Status Register Description
BIT SIGNAL TYPE FUNCTION
7 RSVD R Reserved. Bit 7 returns 0b when read.
6 CARDPWR R
Card Power. Bit 6 indicates the current power status of the PC Card socket. This bit reflects how the ExCA
power control register (ExCA offset 02h/42h/802h, see Section 5.3) is programmed. Bit 6 is encoded as:
0 = V
CC
and V
PP
to the socket turned off (default)
1 = V
CC
and V
PP
to the socket turned on
5 READY R
Ready. Bit 5 indicates the current status of the READY signal at the PC Card interface.
0 = PC Card not ready for data transfer
1 = PC Card ready for data transfer
4 CARDWP R
Card write protect (WP). Bit 4 indicates the current status of WP at the PC Card interface. This signal reports
to the controller whether or not the memory card is write protected. Furthermore, write protection for an entire
16-bit memory window is available by setting the appropriate bit in the memory window offset-address
high-byte register.
0 = WP is 0b. PC Card is read/write.
1 = WP is 1b. PC Card is read-only.
3 CDETECT2 R
Card detect 2. Bit 3 indicates the status of CD2 at the PC Card interface. Software may use this and bit 2
(CDETECT1) to determine if a PC Card is fully seated in the socket.
0 = CD2 is 1b. No PC Card is inserted.
1 = CD2
is 0b. PC Card is at least partially inserted.
2 CDETECT1 R
Card detect 1. Bit 2 indicates the status of CD1 at the PC Card interface. Software may use this and bit 3
(CDETECT2) to determine if a PC Card is fully seated in the socket.
0 = CD1 is 1b. No PC Card is inserted.
1 = CD1
is 0b. PC Card is at least partially inserted.
1−0 BVDSTAT R
Battery voltage detect. When a 16-bit memory card is inserted, the field indicates the status of the battery
voltage detect signals (BVD1, BVD2) at the PC Card interface, where bit 1 reflects the BVD2 status and bit 0
reflects BVD1.
00 = Battery dead
01 = Battery dead
10 = Battery low; warning
11 = Battery good
When a 16-bit I/O card is inserted, this field indicates the status of SPKR
(bit 1) and STSCHG (bit 0) at the
PC Card interface. In this case, the two bits in this field directly reflect the current state of these card outputs.