xr16c864iq Exar Corporation, xr16c864iq Datasheet - Page 9

• Manufacturer Part Number: xr16c864iq
• Description: Quad Uart With Rx/tx Fifo Counters And 128-byte Fifo
• Manufacturer: Exar Corporation

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REV. 2.0.1
The CPU interface is 8 data bits wide with 3 address lines and control signals to execute data bus read and
write transactions. The 864 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 CS# A-D, IOR# and IOW# or CS#, R/W#, A4 and A3
inputs. All four UART channels share the same data bus for host operations. A typical data bus interconnection
for Intel and Motorola mode is shown in
F
2.0 FUNCTIONAL DESCRIPTIONS
2.1
IGURE
3. XR16C864/864D T
CPU Interface
UART_RESET
UART_RESET#
UART_CSC#
UART_CSD#
UART_CSA#
UART_CSB#
UART_INTC
UART_INTD
UART_INTA
UART_INTB
UART_CS#
UART_IRQ#
R/W#
IOW#
IOR#
VCC
A0
A1
A2
A0
A1
A2
D0
D1
D2
D3
D4
D5
D6
D7
D0
D1
D2
D3
D4
D5
D6
D7
A4
A3
YPICAL
Motorola Data Bus (68 Mode) Interconnections
Intel Data Bus (16 Mode) Interconnections
I
NTEL
Figure
/M
OTOROLA
3.
(no connect)
(no connect)
(no connect)
VCC
VCC
9
D
ATA
2.97V TO 5.5V QUAD UART WITH 128-BYTE FIFO
16/68#
CSC#
RESET#
16/68#
CSB#
CSD#
IOW#
CSA#
IOR#
IOW#
CSC#
CSD#
IOR#
CSA#
CSB#
INTC
INTD
RESET
INTD
D0
D1
D2
D3
D4
D5
D6
D7
INTA
INTB
D0
D1
D2
D3
D4
D5
D6
D7
INTA
INTB
INTC
A0
A1
A2
A0
A1
A2
B
US
Channel D
Channel D
Channel A
Channel B
Channel C
Channel A
Channel B
Channel C
I
NTERCONNECTIONS
UART
UART
UART
UART
UART
UART
UART
UART
DTRA#
DSRA#
DTRA#
DSRA#
RTSA#
CTSA#
to Ch A
to Ch A
to Ch A
RTSA#
CTSA#
to Ch A
to Ch A
to Ch A
Similar
Similar
Similar
Similar
Similar
Similar
CDA#
CDA#
GND
GND
RIA#
RIA#
VCC
VCC
TXA
RXA
TXA
RXA
VCC
VCC
Serial Interface of
Serial Interface of
Serial Interface of
RS-232
Serial Interface of
RS-232
RS-232
RS-232
XR16C864