ST16C654D Exar Corporation, ST16C654D Datasheet - Page 9

• Manufacturer Part Number: ST16C654D
• Description: St16c654d -quad Uart With 64-byte Fifo And Infrared Irda Encoder/decoder
• Manufacturer: Exar Corporation

xr
REV. 5.0.2
The CPU interface is 8 data bits wide with 3 address lines and control signals to execute data bus read and
write transactions. The 654 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
4. ST16C654/654D T
CPU Interface
UART_RESET
UART_RESET#
UART_CSC#
UART_CSD#
UART_CSA#
UART_CSB#
UART_INTC
UART_INTD
UART_CS#
UART_IRQ#
UART_INTA
UART_INTB
IOW#
R/W#
IOR#
VCC
A0
A1
A2
A0
A1
A2
D0
D1
D2
D3
D4
D5
D6
D7
D0
D1
D2
D3
D4
D5
D6
D7
A3
A4
YPICAL
Motorola Data Bus (68 Mode) Interconnections
Intel Data Bus (16 Mode) Interconnections
Figure
I
NTEL
/M
4.
OTOROLA
(no connect)
(no connect)
(no connect)
VCC
VCC
9
D
ATA
16/68#
16/68#
CSB#
CSC#
CSD#
IOW#
CSA#
RESET#
IOW#
IOR#
CSC#
CSD#
IOR#
CSA#
CSB#
INTA
INTB
INTC
INTD
RESET
INTD
D0
D1
D2
D3
D4
D5
D6
D7
D0
D1
D2
D3
D4
D5
D6
D7
INTA
INTB
INTC
A0
A1
A2
A0
A1
A2
2.97V TO 5.5V QUAD UART WITH 64-BYTE FIFO
B
US
Channel D
Channel D
Channel A
Channel B
Channel C
Channel A
Channel B
Channel C
I
UART
UART
UART
UART
UART
UART
UART
UART
NTERCONNECTIONS
DSRA#
DSRA#
DTRA#
RTSA#
CTSA#
DTRA#
RTSA#
CTSA#
to Ch A
to Ch A
to Ch A
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
RS-232
RS-232
Serial Interface of
RS-232
ST16C654/654D