SMC Networks SMC91C95 User Manual

Page 10

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10

DESCRIPTION OF PIN FUNCTIONS

PIN NO.

NAME

SYMBOL

TYPE

DESCRIPTION

81

nByte High
Enable

nSBHE

I with pullup

ISA - Byte High Enable input. Asserted (low)
by the system to indicate a data transfer on
the upper data byte.

nCard
Enable 2

nCE2

PCMCIA - Card Enable 2 input. Used to
select card on odd byte accesses.

83

Ready

IOCHRDY

OD24 with

pullup

ISA - Output. Optionally used by the
SMC91C95 to extend host cycles.

nWait

nWAIT

PCMCIA - Output. Optionally used by the
SMC91C95 to extend host cycles.

59, 60,
61, 63,
65, 66,

68-70,
72-74,

76-79

Data Bus

D0-D15

I/O24

Bidirectional. 16 bit data bus used to access
the SMC91C95 internal registers. The data
bus has weak internal pullups. Supports direct
connection to the system bus without external
buffering.

98

Reset

RESET

IS with

pullup

Input. Active high Reset. This input is not
considered active unless it is active for at least
100ns to filter narrow glitches. A POR circuit
generates an internal reset upon power up for
at least 15msec. All hardware reset
references in this spec relate to the OR
function of the POR and the RESET pin.

82

Address
Latch

BALE

IS with

pullup

ISA - Input. Address strobe. For systems that
require address latching, the falling edge of
BALE latches address lines and nSBHE.

nWrite
Enable

nWE

PCMCIA - Write Enable input. Used for
writing into COR and CSR registers as well as
attribute memory space.

90

Interrupt

INTR0

O24

ISA - Active high interrupt signal. The interrupt
line selection is determined by the value of
INT SEL1-0 bits in the Configuration Register.
This interrupt is tri-stated when not selected.

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