MC80F0204 Datasheet, PDF (75/126 Pages) List of Unclassifed Manufacturers – 8-BIT SINGLE-CHIP MICROCONTROLLERS

Preliminary
MC80F0104/0204
16. UNIVERSAL ASYNCHRONOUS RECEIVER/TRANSMITTER (UART)
16.1 UART Serial Interface Functions
The Universal Asynchronous Receiver / Transmitter
(UART) enables full-duplex operation wherein one byte of
data after the start bit is transmitted and received. The on-
chip baud rate generator dedicated to UART enables com-
munications using a wide range of selectable baud rates. In
addition, a baud rate can also be defined by dividing clocks
input to the ACLK pin.
The UART driver consists of RXR, TXR, ASIMR, ASISR
and BRGCR register. Universal asynchronous serial I/O
mode (UART) can be selected by ASIMR register. Figure
16-1 shows a block diagram of the UART driver.
Internal Data Bus
RxE
RxD PIN
TxE
TxD PIN
Receive Buffer Register
(RXR)
Receive Shift Register
(RX)
2
1
0
PE FE OVE (ASISR)
Transmit Shift Register
(TXR)
Transmit Controller
(Parity Addition)
INT_TX
(UART tramsmit interrupt)
ACLK PIN
f_XIN ÷2 ~ f_XIN÷128
Receive Controller
(Parity Check)
Baud Rate
Generator
Figure 16-1 UART Block Diagram
INT_RX
(UART receive interrupt)
Mar. 2005 Ver 0.2
71