xr16m654 Exar Corporation, xr16m654 Datasheet - Page 12

• Manufacturer Part Number: xr16m654
• Description: 1.62v To 3.63v Quad Uart With 64-byte Fifo
• Manufacturer: Exar Corporation

XR16M654/654D
1.62V TO 3.63V QUAD UART 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 M654 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 for 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
5. XR16M654 T
CPU Interface
UART_RESET#
UART_CS#
UART_IRQ#
UART_RESET
UART_CSC#
UART_CSD#
UART_CSA#
UART_CSB#
UART_INTC
UART_INTD
UART_INTA
UART_INTB
R/W#
A0
A1
A2
D0
D1
D2
D3
D4
D5
D6
D7
A3
A4
IOW#
IOR#
VCC
D0
D1
D2
D3
D4
D5
D6
D7
A0
A1
A2
YPICAL
I
VCC
NTEL
Motorola Data Bus (68 Mode) Interconnections
Intel Data Bus (16 Mode) Interconnections
Figure
/M
OTOROLA
5.
(no connect)
(no connect)
(no connect)
D
VCC
VCC
ATA
12
B
US
16/68#
16/68#
IOR#
IOW#
CSB#
CSC#
CSD#
IOW#
CSA#
CSC#
CSD#
RESET
IOR#
INTC
INTD
RESET#
CSA#
CSB#
INTA
INTB
INTC
INTD
INTA
INTB
D0
D1
D2
D3
D4
D5
D6
D7
D0
D1
D2
D3
D4
D5
D6
D7
A0
A1
A2
A0
A1
A2
I
NTERCONNECTIONS
Channel D
Channel C
Channel A
Channel B
Channel D
Channel C
Channel A
Channel B
UART
UART
UART
UART
UART
UART
UART
UART
DTRA#
DSRA#
RTSA#
CTSA#
to Ch A
to Ch A
to Ch A
Similar
Similar
Similar
CDA#
to Ch A
to Ch A
to Ch A
GND
Similar
Similar
Similar
DTRA#
RTSA#
CTSA#
DSRA#
RIA#
VCC
TXA
RXA
CDA#
GND
RIA#
VCC
TXA
RXA
VCC
VCC
Serial Interface of
Serial Interface of
Serial Interface of
RS-232
Serial Interface of
RS-232
RS-232
RS-232
REV. 1.0.0