Datasheet

2−18
Table 2−12. 16-Bit PC Card Interface Control Terminals (Slots A and B) (Continued)
TERMINAL
NUMBER
I/O
DESCRIPTION
NAME
SLOT A
†
SLOT B
‡
I/O
DESCRIPTION
NAME
PDV GHK PDV GHK
OE 99 W15 31 L03 O
Output enable. OE is driven low by the PCI1520 to enable 16-bit memory PC Card data
output during host memory read cycles.
READY
(IREQ
)
138 H19 69 V08 I
Ready. The ready function is provided by READY when the 16-bit PC Card and the host
socket are configured for the memory-only interface. READY is driven low by 16-bit memory
PC Cards to indicate that the memory card circuits are busy processing a previous write
command. READY is driven high when the 16-bit memory PC Card is ready to accept a new
data transfer command.
Interrupt request. IREQ
is asserted by a 16-bit I/O PC Card to indicate to the host that a
device on the 16-bit I/O PC Card requires service by the host software. IREQ
is high
(deasserted) when no interrupt is requested.
REG
132 K14 64 U07 O
Attribute memory select. REG remains high for all common memory accesses. When REG
is asserted, access is limited to attribute memory (OE or WE active) and to the I/O space
(IORD
or IOWR active). Attribute memory is a separately accessed section of card memory
and is generally used to record card capacity and other configuration and attribute
information.
RESET 126 L15 58 W05 O PC Card reset. RESET forces a hard reset to a 16-bit PC Card.
VS1
VS2
137
124
J15
L18
68
56
U08
P07
I/O
Voltage sense 1 and voltage sense 2. VS1 and VS2, when used in conjunction with each
other, determine the operating voltage of the PC Card.
WAIT
139 H18 71 W09 I
Bus cycle wait. WAIT is driven by a 16-bit PC Card to extend the completion of the memory
or I/O cycle in progress.
WE 112 P18 45 N05 O
Write enable. WE is used to strobe memory write data into 16-bit memory PC Cards. WE
is also used for memory PC Cards that employ programmable memory technologies.
WP
(IOIS16
)
142 H15 74 R09 I
Write protect. WP applies to 16-bit memory PC Cards. WP reflects the status of the
write-protect switch on 16-bit memory PC Cards. For 16-bit I/O cards, WP is used for the
16-bit port (IOIS16
) function.
I/O is 16 bits. IOIS16
applies to 16-bit I/O PC Cards. IOIS16 is asserted by the 16-bit PC Card
when the address on the bus corresponds to an address to which the 16-bit PC Card
responds, and the I/O port that is addressed is capable of 16-bit accesses.
†
Terminal name for slot A is preceded with A_. For example, the full name for terminals 112 and P18 is A_WE
.
‡
Terminal name for slot B is preceded with B_. For example, the full name for terminals 45 and N05 is B_WE
.