ST16C450 Exar Corporation, ST16C450 Datasheet - Page 7

• Manufacturer Part Number: ST16C450
• Description: UNIVERSAL ASYNCHRONOUS RECEIVER/TRANSMITTER (UART)
• Manufacturer: Exar Corporation

SYMBOL DESCRIPTION
GENERAL DESCRIPTION
The ST16C450 provides serial asynchronous receive
data synchronization, parallel-to-serial and serial-to-
parallel data conversions for both the transmitter and
receiver sections. These functions are necessary for
converting the serial data stream into parallel data that
is required with digital data systems. Synchronization
for the serial data stream is accomplished by adding
start and stops bits to the transmit data to form a data
character (character orientated protocol). Data integ-
rity is insured by attaching a parity bit to the data
character. The parity bit is checked by the receiver for
any transmission bit errors. The electronic circuitry to
-RI
-RTS
RX
TX
Symbol
Rev. 4.20
32
40
39
10
11
Pin
44
36
11
13
43
48
32
41
7
8
Signal
type
O
O
I
I
Request to Send (active low) - A logic 0 on the -RTS pin
Ring Indicator (active low) - A logic 0 on this pin indicates the
modem has received a ringing signal from the telephone
line. A logic 1 transition on this input pin will generate an
interrupt.
indicates the transmitter has data ready and waiting to send.
Writing a logic 1 in the modem control register (MCR bit-1)
will set this pin to a logic 0 indicating data is available. After
a reset this pin will be set to a logic 1. This pin has no effect
on the UART’s transmit or receive operation.
Receive Data - This pin provides the serial receive data
input to the ST16C450. The RX signal will be a logic 1 during
reset, idle (no data). During the local loop-back mode, the
RX input pin is disabled and TX data is internally connected
to the UART RX Input, internally, see figure 12.
Transmit Data - This pin provides the serial transmit data
from the ST16C450, the TX signal will be a logic 1 during
reset, idle (no data). During the local loop-back mode, the
TX input pin is disabled and TX data is internally connected
to the UART RX Input, see figure 12.
7
provide all these functions is fairly complex especially
when manufactured on a single integrated silicon chip.
The ST16C450 represents such an integration with
greatly enhanced features. The ST16C450 is fabricated
with an advanced CMOS process. The ST16C450 is
designed to work with high speed modems and shared
network environments.
The ST16C450 is capable of operation to 1.5Mbps
with a 24 MHz crystal or external clock input.
With a crystal of 14.7464 MHz and through a software
option, the user can select data rates up to 460.8Kbps
or 921.6Kbps.
Pin Description
ST16C450