The SC28C94A1A ia a quad universal asynchronous receiver/transmitter. 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. The SC28C94A1A provides a power-down mode in which the oscillator is stopped and the register contents are stored. This results in reduced power consumption on the order of several magnitudes. The QUART is fully TTL compatible and operates from a single +5V power supply.
Parity, framing, and overrun error detection
False start bit detection
Line break detection and generation
Programmable channel mode
Normal (full-duplex), automatic echo, local loop back, remote loopback
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
Datasheet Available:Texas Instruments SC28C94A1A
PLCC 52 package. Manufactured by Philips.