sc16c750-04 NXP Semiconductors, sc16c750-04 Datasheet - Page 12

• Manufacturer Part Number: sc16c750-04
• Description: Sc16c750 Universal Asynchronous Receiver/transmitter Uart With 64-byte Fifo
• Manufacturer: NXP Semiconductors

Philips Semiconductors
9397 750 11623
Product data
6.5 Programmable baud rate generator
The SC16C750 supports high speed modem technologies that have increased input
data rates by employing data compression schemes. For example, a 33.6 kbit/s
modem that employs data compression may require a 115.2 kbit/s input data rate.
A 128.0 kbit/s ISDN modem that supports data compression may need an input
data rate of 460.8 kbit/s.
A single baud rate generator is provided for the transmitter and receiver, allowing
independent TX/RX channel control. The programmable Baud Rate Generator is
capable of accepting an input clock up to 48 MHz, as required for supporting a
3 Mbits/s data rate. The SC16C750 can be configured for internal or external clock
operation. For internal clock oscillator operation, an industry standard microprocessor
crystal (parallel resonant/22-33 pF load) is connected externally between the XTAL1
and XTAL2 pins (see
the XTAL1 pin to clock the internal baud rate generator for standard or custom rates
(see
The generator divides the input 16 clock by any divisor from 1 to 2
SC16C750 divides the basic crystal or external clock by 16. The frequency of the
BAUDOUT output pin is exactly 16 (16 times) of the selected baud rate
(BAUDOUT = 16 Baud Rate). Customized baud rates can be achieved by selecting
the proper divisor values for the MSB and LSB sections of baud rate generator.
Programming the Baud Rate Generator registers DLM (MSB) and DLL (LSB)
provides a user capability for selecting the desired final baud rate. The example in
Table 5
For custom baud rates, the divisor value can be calculated using the following
equation:
Divisor (in decimal)
Fig 4. Crystal oscillator connection.
Table
shows selectable baud rates when using a 1.8432 MHz crystal.
5).
Rev. 04 — 20 June 2003
=
C1
47 pF
1.8432 MHz
Figure
XTAL1 clock frequency
---------------------------------------------------------- -
X1
serial data rate 16
4). Alternatively, an external clock can be connected to
C2
100 pF
1.8432 MHz
C1
22 pF
© Koninklijke Philips Electronics N.V. 2003. All rights reserved.
X1
UART with 64-byte FIFO
1.5 k
C2
47 pF
SC16C750
002aaa169
16
1. The
12 of 45
(1)