xr16v2751im Exar Corporation, xr16v2751im Datasheet - Page 8

• Manufacturer Part Number: xr16v2751im
• Description: High Performance Duart With 64-byte Fifo And Powersave Feature
• Manufacturer: Exar Corporation

XR16V2751
HIGH PERFORMANCE DUART WITH 64-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 V2751 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 V2751 can accept up to 5V inputs even when operating at 3.3V or 2.5V. But note that if the V2751 is
operating at 2.5V, its V
transceiver that is operating at 5V. Caution: XTAL1 is not 5 volt tolerant.
F
2.0 FUNCTIONAL DESCRIPTIONS
2.1
2.2
IGURE
3. XR16V2751 T
CPU Interface
5-Volt Tolerant Inputs
UART_RESET
UART_RESET#
UART_CSA#
UART_CSB#
UART_IRQ#
UART_CS#
UART_INTA
UART_INTB
TXRDYA#
RXRDYA#
TXRDYB#
RXRDYB#
RXRDYA#
RXRDYB#
TXRDYA#
TXRDYB#
R/W#
IOW #
IOR#
A0
A1
A2
D0
D1
D2
D3
D4
D5
D6
D7
A3
A0
A1
A2
D0
D1
D2
D3
D4
D5
D6
D7
OH
YPICAL
may not be high enough to meet the requirements of the V
Figure
I
NTEL
/M
Motorola Data Bus Interconnections
3.
Intel Data Bus Interconnections
OTOROLA
VCC
(no connect)
VCC
D
ATA
8
B
RESET#
CSB#
IOW#
CSA#
IOR#
INTA
INTB
TXRDYA#
RXRDYA#
TXRDYB#
RXRDYB#
IOR#
IOW #
CSA#
CSB#
D0
D1
D2
D3
D4
D5
D6
D7
RESET
US
INTA
INTB
TXRDYA#
RXRDYA#
TXRDYB#
RXRDYB#
A0
A1
A2
D0
D1
D2
D3
D4
D5
D6
D7
A0
A1
A2
I
NTERCONNECTIONS
Channel A
Channel B
Channel A
Channel B
UART
UART
UART
UART
DTRA#
RTSA#
CTSA#
DSRA#
DSRB#
DTRB#
RTSB#
CTSB#
DTRA#
DSRA#
OP2A#
RTSA#
CTSA#
DTRB#
DSRB#
OP2B#
OP2A#
RTSB#
CTSB#
OP2B#
CDA#
CDB#
CDA#
CDB#
GND
RIA#
GND
RIB#
VCC
TXA
RXA
RIA#
TXB
RXB
VCC
RIB#
TXA
RXA
RXB
TXB
2.25 to 5.5 Volt VCC
VCC
(no connect)
(no connect)
(no connect)
(no connect)
RS-232 Serial Interface
RS-232 Serial Interface
Serial Interface of
Serial Interface of
RS-232, RS-485
RS-232, RS-485
IH
of a CPU or a serial
2750_int
REV. 1.0.1