xr16m2751 Exar Corporation, xr16m2751 Datasheet - Page 8

• Manufacturer Part Number: xr16m2751
• Description: High Performance Duart With 64-byte Fifo And Powersave
• Manufacturer: Exar Corporation

XR16M2751
1.62V TO 3.63V HIGH PERFORMANCE DUART WITH 64-BYTE FIFO
The CPU interface is 8 data bits wide with 3 address lines and control signals to execute data bus read and
write transactions. The M2751 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 RESET input resets the internal registers and the serial interface outputs in both channels to their default
state (see
function in the device.
F
2.0 FUNCTIONAL DESCRIPTIONS
2.1
2.2
IGURE
3. XR16M2751 T
CPU Interface
Device Reset
Table
UART_RESET
UART_RESET#
UART_CSA#
UART_CSB#
UART_IRQ#
UART_CS#
UART_INTA
UART_INTB
TXRDYA#
RXRDYA#
TXRDYB#
RXRDYB#
RXRDYA#
RXRDYB#
TXRDYA#
TXRDYB#
17). An active high pulse of longer than 40 ns duration will be required to activate the reset
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
YPICAL
Figure
I
NTEL
Motorola Data Bus Interconnections
/M
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
INTA
INTB
TXRDYA#
RXRDYA#
TXRDYB#
RXRDYB#
A0
A1
A2
D0
D1
D2
D3
D4
D5
D6
D7
A0
A1
A2
US
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
2750_int
REV. 1.0.0