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CHAPTER 13 UART
13.1 Overview of UART
UART is a general-purpose serial data communication interface for performing
synchronous or asynchronous (start-stop synchronization) communication with
external devices. The UART has a bidirectional communication function (normal
mode), additionally the master-slave communication function (multiprocessor mode) is
only available for the master system.
s UART Functions
r UART Functions
UART is a general-purpose serial data communication interface for transmitting serial data to
and receiving data from another CPU and peripheral devices. It has the functions listed in
TableTable 13.1-1 UART Functions
Function
Data buffer
Full-duplex, double buffering
Transfer mode
Clock synchronous (using start and stop bits)
Clock asynchronous (start-stop synchronization)
Baud rate
Up to 2MHz (when the machine clock is operated at 16MHz)
A dedicated baud rate generator is provided.
Baud rate by an external clock (clock input through the SCK0/SCK1 pins)
Internal clock (internal clocks supplied from 16-bit reload timer 0 can be used.)
The baud rate can be selected from a total of eight types
Data length
7 bits (in asynchronous normal mode only)
8 bits
Signal mode
Non-return to zero (NRZ)
Reception error
detection
Framing error
Overrun error
Parity error (cannot be detected in multiprocessor mode.)
Interrupt request
Reception interrupt (reception completion and reception error detection)
Transmission interrupt (transmission completion)
Extended intelligent I/O service (EI20S) is available for both transmission and
reception interrupts.
Master-slave
communication
function
(multiprocessor
mode
One-to-n communication (one master to n slaves) can be performed. (This function is
supported only for the master system.)