saa-xc866 Infineon Technologies Corporation, saa-xc866 Datasheet - Page 70

• Manufacturer Part Number: saa-xc866
• Description: 8-bit Single-chip Microcontroller
• Manufacturer: Infineon Technologies Corporation

3.11
The Universal Asynchronous Receiver/Transmitter (UART) provides a full-duplex
asynchronous receiver/transmitter, i.e., it can transmit and receive simultaneously. It is
also receive-buffered, i.e., it can commence reception of a second byte before a
previously received byte has been read from the receive register. However, if the first
byte still has not been read by the time reception of the second byte is complete, one of
the bytes will be lost.
Features:
• Full-duplex asynchronous modes
• Receive buffered
• Multiprocessor communication
• Interrupt generation on the completion of a data transmission or reception
The UART can operate in four asynchronous modes as shown in
transmitted on TXD and received on RXD.
Table 25
Operating Mode
Mode 1: 8-bit shift UART
Mode 2: 9-bit shift UART
Mode 3: 9-bit shift UART
There are several ways to generate the baud rate clock for the serial port, depending on
the mode in which it is operating. In mode 0, the baud rate for the transfer is fixed at
f
and can be configured to either f
either the underflow rate on the dedicated baud-rate generator, or by the overflow rate
on Timer 1.
Data Sheet
PCLK
Mode 0: 8-bit shift register
– 8-bit or 9-bit data frames, LSB first
– fixed or variable baud rate
/2. In mode 2, the baud rate is generated internally based on the UART input clock
Universal Asynchronous Receiver/Transmitter
UART Modes
PCLK
/32 or f
Baud Rate
f
Variable
f
Variable
PCLK
PCLK
66
PCLK
/2
/32 or f
/64. The variable baud rate is set by
PCLK
/64
Functional Description
Table
SAA-XC866
V1.2, 2008-02
25. Data is