Philips Semiconductors Product specification
SC26C92
Dual universal asynchronous receiver/transmitter (DUART)
2
2000 Jan 31 853–1585 23061
DESCRIPTION
The SC26C92 is a pin and function replacement for the SCC2692
and SCN2681 with added features and deeper FIFOs. Its
configuration on power up is that of the 2692. Its differences from
the 2692 are: 8 character receiver, 8 character transmit FIFOs,
watch dog timer for each receiver, mode register 0 is added,
extended baud rate and overall faster speeds, programmable
receiver and transmitter interrupts. (The SCC2692 is not being
discontinued.)
The Philips Semiconductors SC26C92 Dual Universal
Asynchronous Receiver/Transmitter (DUART) is a single-chip
CMOS-LSI communications device that provides two full-duplex
asynchronous receiver/transmitter channels in a single package. It
interfaces directly with microprocessors and may be used in a polled
or interrupt driven system and provides modem and DMA interface.
The operating mode and data format of each channel can be
programmed independently. Additionally, each receiver and
transmitter can select its operating speed as one of 27 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 DUART particularly
attractive for dual-speed channel applications such as clustered
terminal systems.
Each receiver and transmitter is buffered by eight character FIFOs
to minimize the potential of receiver overrun, transmitter underrun
and to reduce interrupt overhead in interrupt driven systems. In
addition, a flow control capability is provided via RTS/CTS signaling
to disable a remote transmitter when the receiver buffer is full.
Also provided on the SC26C92 are a multipurpose 7-bit input port
and a multipurpose 8-bit output port. These can be used as general
purpose I/O ports or can be assigned specific functions (such as
clock inputs or status/interrupt outputs) under program control.
The SC26C92 is available in three package versions: 40-pin 0.6”
wide DIP, a 44-pin PLCC and 44–pin plastic quad flat pack (PQFP).
FEATURES
• Dual full-duplex independent asynchronous receiver/transmitters
• 8 character FIFOs for each receiver and transmitter
• 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
• 16-bit programmable Counter/Timer
• Programmable baud rate for each receiver and transmitter
selectable from:
– 27 fixed rates: 50 to 230.4k baud
– Other baud rates to 230.4k baud at 16X
– Programmable user-defined rates derived from a
programmable counter/timer
– External 1X or 16X clock
• Parity, framing, and overrun error detection
• False start bit detection
• Line break detection and generation
• Programmable channel mode
– Normal (full-duplex)
– Automatic echo
– Local loopback
– Remote loopback
– Multidrop mode (also called ‘wake-up’ or ‘9-bit’)
• Multi-function 7-bit input port
– Can serve as clock, modem, or control inputs
– Change of state detection on four inputs
– Inputs have typically >100k pull-up resistors
• Multi-function 8-bit output port
– Individual bit set/reset capability
– Outputs can be programmed to be status/interrupt signals
– FIFO states for DMA and modem interface
• Versatile interrupt system
– Single interrupt output with eight maskable interrupting
conditions
– Output port can be configured to provide a total of up to six
separate wire-ORable interrupt outputs
– Each FIFO can be programmed for four different interrupt levels
– Watch dog timer for each receiver
• Maximum data transfer rates:
1X – 1Mb/sec, 16X – 1Mb/sec
• Automatic wake-up mode for multidrop applications
• Start-end break interrupt/status
• Detects break which originates in the middle of a character
• On-chip crystal oscillator
• Power down mode
• Receiver timeout mode
• Single +5V power supply
• Powers up to emulate SCC2692
ORDERING INFORMATION
COMMERCIAL
1
INDUSTRIAL
V
CC
= +5V ±10%, T
A
= 0 to +70°C V
CC
= +5V ±10%, T
A
= -40 to +85°C
40-Pin Plastic Dual In-Line Package (DIP) SC26C92C1N SC26C92A1N SOT129-1
44-Pin Plastic Leaded Chip Carrier (PLCC) SC26C92C1A SC26C92A1A SOT187-2
44–Pin Plastic Quad Flat Pack (PQFP) SC26C92C1B SC26C92A1B SOT307–2
