TL16C450_09 Datasheet, PDF (24/27 Pages) Texas Instruments – ASYNCHRONOUS COMMUNICATIONS ELEMENT

TL16C450
ASYNCHRONOUS COMMUNICATIONS ELEMENT
SLLS037C − MARCH 1988 − REVISED JANUARY 2006
PRINCIPLES OF OPERATION
receiver buffer register (RBR)
The ACE receiver section consists of a receiver shift register and a RBR. Timing is supplied by the 16× receiver
clock (RCLK). Receiver section control is a function of the ACE line control register.
The ACE receiver shift register receives serial data from the serial input (SIN) terminal. The receiver shift
register then converts the data to a parallel form and loads it into the RBR. When a character is placed in the
RBR and the received data available interrupt is enabled, an interrupt is generated. This interrupt is cleared
when the data is read out of the RBR.
scratch register
The scratch register is an 8-bit register that is intended for programmer use as a scratchpad, in the sense that
it temporarily holds programmer data without affecting any other ACE operation.
transmitter holding register (THR)
The ACE transmitter section consists of a THR and a transmitter shift register. Timing is supplied by the baud
out (BAUDOUT) clock signal. Transmitter section control is a function of the ACE line control register.
The ACE THR receives data from the internal data bus and, when the shift register is idle, moves it into the
transmitter shift register. The transmitter shift register serializes the data and outputs it at the serial output
(SOUT). If the THR is empty and the transmitter holding register empty (THRE) interrupt is enabled, an interrupt
is generated. This interrupt is cleared when a character is loaded into the register.
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