XR16M554 Datasheet, PDF (5/46 Pages) Exar Corporation – 1.62V TO 3.63V QUAD UART WITH 16-BYTE FIFO

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Pin Description
XR16M554/554D
1.62V TO 3.63V QUAD UART WITH 16-BYTE FIFO
NAME
48-QFN
PIN #
64-LQFP
PIN #
68-PLCC
PIN#
80-LQFP
PIN #
TYPE
DESCRIPTION
CSB#
9
(A3)
11
20
33
I When 16/68# pin is HIGH, this input is chip select B
(active low) to enable channel B in the device.
When 16/68# pin is LOW, this input becomes address
line A3 which is used for channel selection in the Motor-
ola bus interface.
CSC#
27
38
50
68
I When 16/68# pin is HIGH, this input is chip select C
(A4)
(active low) to enable channel C in the device.
When 16/68# pin is LOW, this input becomes address
line A4 which is used for channel selection in the Motor-
ola bus interface.
CSD#
31
42
54
73
I When 16/68# pin is HIGH, this input is chip select D
(VCC)
(active low) to enable channel D in the device.
When 16/68# pin is LOW, this input is not used and
should be connected VCC.
INTA
4
(IRQ#)
6
15
27
O When 16/68# pin is HIGH for Intel bus interface, this
(OD) ^{ouput becomes channel A interrupt output. The output}
state is defined by the user and through the software
setting of MCR[3]. INTA is set to the active mode when
MCR[3] is set to a logic 1. INTA is set to the three state
mode when MCR[3] is set to a logic 0 (default). See
MCR[3].
When 16/68# pin is LOW for Motorola bus interface,
this output becomes device interrupt output (active low,
open drain). An external pull-up resistor is required for
proper operation.
INTB
10
12
21
34
O When 16/68# pin is HIGH for Intel bus interface, these
INTC
26
37
49
67
INTD
32
43
55
74
(N.C.)
ouputs become the interrupt outputs for channels B, C,
and D. The output state is defined by the user through
the software setting of MCR[3]. The interrupt outputs
are set to the active mode when MCR[3] is set to a logic
1 and are set to the three state mode when MCR[3] is
set to a logic 0 (default). See MCR[3].
When 16/68# pin is LOW for Motorola bus interface,
these outputs are unused and will stay at logic zero
level. Leave these outputs unconnected.
TXRDY#
-
-
39
55
O Transmitter Ready (active low). This output is a logi-
cally ANDed status of TXRDY# A-D. See Table 5. If this
output is unused, leave it unconnected.
RXRDY#
-
-
38
54
O Receiver Ready (active low). This output is a logically
ANDed status of RXRDY# A-D. See Table 5. If this out-
put is unused, leave it unconnected.
5