xr16m890 Exar Corporation, xr16m890 Datasheet - Page 9

• Manufacturer Part Number: xr16m890
• Description: Uart With 128-byte Fifo And Integrated Level Shifters
• Manufacturer: Exar Corporation

REV. P1.1.1
There are 3 CPU interfaces that can be selected on the XR16M890. They are the Intel, Motorola and VLIO
bus interfaces. Note: no clock (crystal or external clock) is required for data bus transactions. Each bus cycle
is asynchronous.
The Intel bus interface consists of 8 data bits, 3 address lines and 3 control signals (CS#, IOR# and IOW#) for
data bus read/write transactions. In this mode, the interrupt output (INT) is active high. A typical data bus
interconnection is shown in
The Motorola bus interface is similar to the Intel bus interface. This interface consists of 8 data bits, 3 address
lines, but only 2 control signals (CS# and R/W#) for data bus read/write transactions. In this mode, the
interrupt output (IRQ#) is an open-drain and active low. A typical data bus interconnection is shown in
Figure
F
F
1.0 FUNCTIONAL DESCRIPTIONS
1.1
1.1.1
1.1.2
IGURE
IGURE
S L E E P /P W R D N
S L E E P /P W R D N
U A R T _ R E S E T
U A R T _ R E S E T #
U A R T _ IO W #
U A R T _ IO R #
U A R T _ C S #
5.
4. XR16M890 T
5. XR16M890 T
U A R T _ IR Q #
U A R T _ C S #
CPU Interface
U A R T _ IN T
Intel bus interface (16 mode)
Motorola bus interface (68 mode)
R /W #
A 0
A 1
A 2
D 0
D 1
D 2
D 3
D 4
D 5
D 6
D 7
D 0
D 1
D 2
D 3
D 4
D 5
D 6
D 7
A 0
A 1
A 2
YPICAL
YPICAL
Figure
I
M
NTEL
OTOROLA
4.
D
UART WITH 128-BYTE FIFO AND INTEGRATED LEVEL SHIFTERS
ATA
v c c
D
B
ATA
US
I
NTERCONNECTION
B
PRELIMINARY
US
V C C
I
NTERCONNECTIONS
9
S L E E P /P W R D N
IO R #
IO W #
C S #
S L E E P /P W R D N
D 0
D 1
D 2
D 3
D 4
D 5
D 6
D 7
IN T
R E S E T
R E S E T #
A 0
A 1
A 2
IO R #
IO W #
IR Q #
D 0
D 1
D 2
D 3
D 4
D 5
D 6
D 7
A 0
A 1
A 2
C S #
V C C _ B U S
V C C _ B U S
V L IO _ E N
V L IO _ E N
1 6 /6 8 #
1 6 /6 8 #
D S R #
D T R #
R T S #
C T S #
G N D
D T R #
D S R #
R T S #
C T S #
G N D
C D #
C D #
R I#
T X
R I#
R X
T X
R X
V C C _ B U S
V C C _ B U S
S e ria l T ra n s c e iv e rs o f
S e ria l T ra n s c e ive rs o f
O r In fra re d
O r In fra re d
XR16M890
R S -2 3 2
R S -4 8 5
R S -4 2 2
R S -2 3 2
R S -4 8 5
R S -4 2 2