XR16M2752
3
REV. 1.0.0
1.62V TO 3.63V HIGH PERFORMANCE DUART WITH 64-BYTE FIFO
PIN DESCRIPTIONS
Pin Description
NAME
32-QFN
PIN #
44-PLCC
PIN #
TYPE
DESCRIPTION
DATA BUS INTERFACE
A2
A1
A0
7
6
3
15
14
10
I
Address data lines [2:0]. These 3 address lines select one of the internal
registers in UART channel A/B during a data bus transaction.
D7
D6
D5
D4
D3
D2
D1
D0
2
1
32
31
30
29
28
27
9
8
7
6
5
4
3
2
I/O
Data bus lines [7:0] (bidirectional).
IOR#
14
24
I
Input/Output Read Strobe (active low). The falling edge instigates an inter-
nal read cycle and retrieves the data byte from an internal register pointed
to by the address lines [A2:A0]. The data byte is placed on the data bus to
allow the host processor to read it on the rising edge.
IOW#
11
20
I
Input/Output Write Strobe (active low). The falling edge instigates an inter-
nal write cycle and the rising edge transfers the data byte on the data bus
to an internal register pointed by the address lines.
CS#
10
18
I
UART chip select (active low). This function selects channel A or B in
accordance with the logical state of the CHSEL pin. This allows data to be
transferred between the user CPU and the 2752.
CHSEL
8
16
I
Channel Select - UART channel A or B is selected by the logical state of
this pin when the CS# pin is a logic 0. A logic 0 on the CHSEL selects the
UART channel B while a logic 1 selects UART channel A. Normally,
CHSEL could just be an address line from the user CPU such as A4. Bit-0
of the Alternate Function Register (AFR) can temporarily override CHSEL
function, allowing the user to write to both channel register simultaneously
with one write cycle when CS# is low. It is especially useful during the ini-
tialization routine.
INTA
21
34
O
UART channel A Interrupt output (active high). A logic high indicates chan-
nel A is requesting for service. For more details, see
INTB
9
17
O
UART channel B Interrupt output (active high). A logic high indicates chan-
nel B is requesting for service. For more details, see
TXRDYA#
-
1
O
UART channel A Transmitter Ready (active low). The output provides the
TX FIFO/THR status for transmit channel A. See
TXRDYB#
-
32
O
UART channel B Transmitter Ready (active low). The output provides the
TX FIFO/THR status for transmit channel B.
MODEM OR SERIAL I/O INTERFACE
TXA
23
38
O
UART channel A Transmit Data or infrared encoder data. Standard trans-
mit and receive interface is enabled when MCR[6] = 0. In this mode, the
TX signal will be HIGH during reset or idle (no data). Infrared IrDA transmit
and receive interface is enabled when MCR[6] = 1. In the Infrared mode,
the inactive state (no data) for the Infrared encoder/decoder interface is
LOW. If it is not used, leave it unconnected.