SC28C94 Philips Semiconductors, SC28C94 Datasheet - Page 2

• Manufacturer Part Number: SC28C94
• Description: Quad universal asynchronous receiver/transmitter QUART
• Manufacturer: Philips Semiconductors

stopped and the register contents are stored. This results in reduced
Philips Semiconductors
DESCRIPTION
The 28C94 quad universal asynchronous receiver/transmitter
(QUART) combines four enhanced Philips Semiconductors
industry-standard UARTs with an innovative interrupt scheme that
can vastly minimize host processor overhead. It is implemented
using Philips Semiconductors’ high-speed CMOS process that
combines small die size and cost with low power consumption.
The operating speed of each receiver and transmitter can be
selected independently at one of eighteen fixed baud rates, a 16X
clock derived from a programmable counter/timer, or an external 1X
or 16X clock. The baud rate generator and counter/timer can
operate directly from a crystal or from external clock inputs. The
ability to independently program the operating speed of the receiver
and transmitter make the QUART particularly attractive for
dual-speed channel applications such as clustered terminal
systems.
Each receiver is buffered with eight character FIFOs (first-in-first-out
memories) and one shift register to minimize the potential for
receiver overrun and to reduce interrupt overhead in interrupt driven
systems. In addition, a handshaking capability is provided to disable
a remote UART transmitter when the receiver buffer is full. (RTS
control)
The 28C94 provides a power-down mode in which the oscillator is
power consumption on the order of several magnitudes. The
QUART is fully TTL compatible and operates from a single +5V
power supply.
FEATURES
ORDERING INFORMATION
1998 Aug 19
48-Pin Plastic Dual In-Line Package (DIP)
52-Pin Plastic Leaded Chip Carrier (PLCC) Package
New low overhead interrupt control
All commercial parts meet industrial timing and temperature
parameters
Four Philips Semiconductors industry-standard UARTs
Eight byte receive FIFO and eight byte transmit FIFO for each
UART
Programmable data format:
– 5 to 8 data bits plus parity
– Odd, even, no parity or force parity
– 1, 1.5 or 2 stop bits programmable in 1/16-bit increments
Baud rate for the receiver and transmitter selectable from:
– 23 fixed rates: 50 to 230.4K baud Non-standard rates to 1.0M
– User-defined rates from the programmable counter/timer
– External 1x or 16x clock
Parity, framing, and overrun error detection
False start bit detection
Line break detection and generation
Quad universal asynchronous receiver/transmitter (QUART)
baud
associated with each of two blocks
PACKAGES
C
G S
2
PIN CONFIGURATIONS
Programmable channel mode
– Normal (full-duplex), automatic echo, local loop back, remote
Programmable interrupt priorities
Identification of highest priority interrupt
Global interrupt register set provides data from interrupting
channel
Vectored interrupts with programmable vector format
IACKN and programmable DTACKN signals
Built-in baud rate generator with choice of 18 rates
Four I/O pins per UART for modem controls, clocks, etc.
Power down mode
High-speed CMOS technology
52-pin PLCC and 48-pin DIP
Commercial and industrial temperature ranges available
On-chip crystal oscillator
TTL compatible
Single +5V power supply with low power mode
Two multifunction programmable 16-bit counter/timers
1MHz 16x mode operation
10ns data bus release time
“Watch Dog” timer for each receiver
loopback
X1/CLK
RESET
RDa-d
T
WRN
RDN
A5:0
CEN
D7-0
A
V
Figure 1. Pin Configuration
X2
CC
= –40
SC28C94A1N
SC28C94A1A
INDUSTRIAL
= +5V +10%,
o
C to +85
V
V
CC
SS
o
C
Product specification
SD00158
IACKN
DACKN
RQN
I/O0a–d
I/O1a–d
I/O2a–d
I/O3a–d
TDa-d
SC28C94
853–2111 19896
SOT240-1
SOT238-3
DWG #
G