XR18W750 Datasheet, PDF (3/44 Pages) Exar Corporation – WIRELESS UART CONTROLLER

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PIN DESCRIPTIONS
XR18W750
WIRELESS UART CONTROLLER
Pin Description
NAME
48-QFN
PIN #
TYPE
DESCRIPTION
PARALLEL MODE INTERFACE SIGNALS
A2
A1
A0
D7
D6
D5
D4
D3
D2
D1
D0
IOR#
(VCC)
23
I _{Address data lines [2:0]. These 3 address lines select one of the internal regis-}
22
ters in the UART during a data bus transaction. The internal UART registers are
21
not accessed by the 8051 microprocessor in the parallel mode.
34
I/O _{Data bus lines [7:0] (bidirectional).}
33
32
31
30
29
28
27
26
I _{When 16/68# pin is HIGH, the Intel bus interface is selected and this input}
becomes read strobe (active low). The falling edge instigates an internal read
cycle and retrieves the data byte from an internal register pointed by the address
lines [A2:A0], puts the data byte on the data bus to allow the host processor to
read it on the rising edge.
When 16/68# pin is LOW, the Motorola bus interface is selected and this input is
not used and should be connected to VCC.
IOW#
(R/W#)
18
I _{When 16/68# pin is HIGH, it selects Intel bus interface and this input becomes}
write strobe (active low). The falling edge instigates the internal write cycle and
the rising edge transfers the data byte on the data bus to an internal register
pointed by the address lines.
When 16/68# pin is LOW, the Motorola bus interface is selected and this input
becomes read (HIGH) and write (LOW) signal.
CS#
19
I _{Chip select (active low) signal.}
INT
(IRQ#)
47
O _{When 16/68# pin is HIGH for Intel bus interface, this output is an active high}
interrupt output. Upon power-up, this output is in three-state mode. The output
state is controlled by the user through the software setting of MCR[3]. The INT
output is enabled when MCR[3] is set to a logic 1. See MCR[3].
When 16/68# pin is LOW for Motorola bus interface, this output becomes an
active low, open drain interrupt output. An external pull-up resistor is required for
proper operation.
TXRDY#
35
O _{UART Transmitter Ready (active low). The output provides the TX FIFO/THR sta-}
tus for transmit. See Table 3. If it is not used, leave it unconnected.
RXRDY#
20
O _{UART Receiver Ready (active low). This output provides the RX FIFO/RHR sta-}
tus for receive. See Table 3. If it is not used, leave it unconnected.
SERIAL MODE INTERFACE SIGNALS
TX
44
O _{UART Transmit Data. Standard transmit and receive interface is enabled when}
MCR[6] = 0. In this mode, the TX signal will be HIGH during reset or idle (no
data). If this pin is not used, leave it unconnected.
RX
43
I _{UART Receive Data. Normal receive data input must idle HIGH. If this pin is not}
used, tie it to VCC or pull it high via a 100k ohm resistor.
3