xr16v2651im Exar Corporation, xr16v2651im Datasheet - Page 8

• Manufacturer Part Number: xr16v2651im
• Description: High Performance Duart With 32-byte Fifo And Powersave
• Manufacturer: Exar Corporation

XR16V2651
HIGH PERFORMANCE DUART WITH 32-BYTE FIFO AND POWERSAVE FEATURE
The CPU interface is 8 data bits wide with 3 address lines and control signals to execute data bus read and
write transactions. The V2651 data interface supports the Intel compatible types of CPUs and it is compatible
to the industry standard 16C550 UART. No clock (oscillator nor external clock) is required to operate a data
bus transaction. Each bus cycle is asynchronous using CSA/B#, IOR# and IOW# or CS#, R/W# and A3 inputs.
Both UART channels share the same data bus for host operations. A typical data bus interconnection for Intel
and Motorola mode is shown in
The V2651 can accept up to 5V inputs even when operating at 3.3V or 2.5V. But note that if the V2651 is
operating at 2.5V, its V
transceiver that is operating at 5V.
F
2.0 FUNCTIONAL DESCRIPTIONS
2.1
2.2
IGURE
3. XR16V2651 T
CPU Interface
5-Volt Tolerant Inputs
U ART_RESET#
UAR T_C SA#
UAR T_C SB#
UAR T_R ESET
UAR T_IR Q #
U ART_INTA
U ART_INTB
UAR T_C S#
RXR D YA#
RXR D YB#
TXR DYA#
TXR DYB#
RXR D YA#
RXR D YB#
TXR DYA #
TXR DYB #
IO W #
R /W #
IO R #
A0
A1
A2
D 0
D 1
D 2
D 3
D 4
D 5
D 6
D 7
A0
A1
A2
A3
D 0
D 1
D 2
D 3
D 4
D 5
D 6
D 7
OH
YPICAL
may not be high enough to meet the requirements of the V
Figure
I
NTEL
/M
M otorola Data Bus Interconnections
3.
Intel Data Bus Interconnections
OTOROLA
VCC
(no connect)
D
VCC
ATA
8
B
TXRDYA#
R XRD YA#
TXRDYB#
R XRD YB#
US
IO R #
IO W #
C SA#
C SB#
INTA
INTB
RESET
TXRD YA#
R XRD YA#
TXRD YB#
R XRD YB#
D 0
D 1
D 2
D 3
D 4
D 5
D 6
D 7
C SB#
IO R #
IO W #
CSA#
IN TA
IN TB
A 0
A 1
A 2
R ESET#
D0
D1
D2
D3
D4
D5
D6
D7
A0
A1
A2
I
NTERCONNECTIONS
Channel A
Channel B
C hannel A
C hannel B
UAR T
UAR T
U ART
U ART
D TR B #
D SRB#
D TR A#
DSR A#
O P2A#
D TR B#
DSR B#
O P2B#
D SRA#
O P2A#
R TSB#
C TSB#
O P2B#
RTSA#
CTSA#
RTSB#
CTSB#
DTRA#
R TSA#
C TSA#
C DA#
C DB#
C D A#
CD B#
RIA#
RIB#
G N D
RIA#
G ND
TXB
RXB
RIB#
TXA
R XA
TXB
R XB
VCC
VC C
TXA
RXA
VC C
2.25 to 3.6 Volt VC C
(no connect)
(no connect)
(no connect)
(no connect)
Serial Interface of
Serial Interface of
Serial Interface of
Serial Interface of
RS-232, R S-422
RS-232, R S-422
R S-232, RS-422
R S-232, RS-422
IH
of a CPU or a serial
REV. 1.0.2