User Manual
622
Rev. 1.1
2019-03-18
TLE984xQX
Microcontroller with LIN and Power Switches for Automotive Applications
UART1/UART2
19
UART1/UART2
19.1
Features
• Full-duplex asynchronous modes
– 8-Bit or 9-Bit data frames, LSB first
– fixed or variable baud rate
• Receive buffered (1 Byte)
• Multiprocessor communication
• Interrupt generation on the completion of a data transmission or reception
• Baud-rate generator with fractional divider for generating a wide range of baud rates, e.g. 9.6kBaud,
19.2kBaud, 115.2kBaud, 125kBaud, 250kBaud, 500kBaud
• Hardware logic for break and sync byte detection
• for UART1: LIN support: connected to timer channel for synchronization to LIN baud rate
In all modes, transmission is initiated by any instruction that uses SBUF as a destination register. Reception is
initiated in the modes by the incoming start bit if REN = 1.
The serial interface also provides interrupt requests when transmission or reception of the frames has been
completed. The corresponding interrupt request flags are TI or RI, respectively. If the serial interrupt is not
used (i.e., serial interrupt not enabled), TI and RI can also be used for polling the serial interface.
19.2
Introduction
The UART1/UART2 provide a full-duplex asynchronous receiver/transmitter, i.e., it can transmit and receive
simultaneously. They are also receive-buffered, i.e., they 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, the previous byte will be lost. The serial port receive
and transmit registers are both accessed at Special Function Register (SFR) SBUF. Writing to SBUF loads the
transmit register, and reading SBUF accesses a physically separate receive register.