XR16M752_09 Datasheet, PDF (10/54 Pages) Exar Corporation – HIGH PERFORMANCE DUART WITH 64-BYTE FIFO

XR16M752/XR68M752
HIGH PERFORMANCE DUART WITH 64-BYTE FIFO
REV. 1.1.1
2.0 FUNCTIONAL DESCRIPTIONS
2.1 CPU Interface
The CPU interface is 8 data bits wide with 3 address lines and control signals to execute data bus read and
write transactions. The XR16M752 data interface supports the Intel compatible types of CPUs while the
XR68M752 supports both the Intel and Motorola compatible data interfaces. No clock (oscillator nor external
clock) is required to operate a data bus transaction. Each bus cycle is asynchronous using CS#, IOR# and
IOW# signals. Both UART channels share the same data bus for host operations. The data bus
interconnections are shown in Figure 4.
FIGURE 4. XR16M752/XR68M752 DATA BUS INTERCONNECTIONS
D0
D1
D2
D3
D4
D5
D6
D7
A0
A1
A2
IO R #
IO W #
UART_CSA#
UART_CSB#
UART_INTA
UART_INTB
TXRDYA#
RXRDYA#
TXRDYB#
RXRDYB#
UART_RESET
D0
D1
D2
D3
D4
D5
D6
D7
A0
A1
A2
A3
R /W #
UART_CS#
UART_IRQ#
TXRDYA#
RXRDYA#
TXRDYB#
RXRDYB#
UART_RESET#
D0
D1
D2
D3
D4
D5
D6
D7
A0
A1
A2
IO R #
IO W #
CSA#
CSB#
INTA
INTB
TXRDYA#
RXRDYA#
TXRDYB#
RXRDYB#
VCC
UART
Channel A
TXA
RXA
DTRA#
RTSA#
CTSA#
DSRA#
CDA#
RIA#
OP2A#
UART
Channel B
TXB
RXB
DTRB#
RTSB#
CTSB#
DSRB#
CDB#
RIB#
OP2B#
RESET
GND
VCC
Serial Interface of
RS-232, RS-422
or RS-485
(no connect)
Serial Interface of
RS-232, RS-422
or RS-485
(no connect)
Intel Data Bus Interconnections
VCC
VCC
(no connect)
D0
D1
D2
D3
D4
D5
D6
D7
A0
A1
A2
CSB#
IO R #
IO W #
CSA#
INTA
INTB
TXRDYA#
RXRDYA#
TXRDYB#
RXRDYB#
RESET#
VCC
UART
Channel A
TXA
RXA
DTRA#
RTSA#
CTSA#
DSRA#
CDA#
RIA#
OP2A#
TXB
RXB
DTRB#
UART ^RTSB#
Channel B CTSB#
DSRB#
CDB#
RIB#
OP2B#
GND
2.25 to 3.6 Volt VCC
Serial Interface of
RS-232, RS-422
or RS-485
(no connect)
Serial Interface of
RS-232, RS-422
or RS-485
(no connect)
Motorola Data Bus Interconnections
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