Overview; Features - Samsung S3C2500B User Manual

S3C2500B
14

14.1 OVERVIEW

The S3C2500B High-Speed UART (Universal Asynchronous Receiver/Transmitter) unit provides two independent
asynchronous serial I/O (SIO) ports. High-Speed UART can operate in interrupt-based or DMA-based mode
(DMA 0, 1, 2 for High-Speed UART Channel 0, DMA 3,4,5 for High-Speed UART Channel 1) That is, the High-
Speed UART can generate internal interrupts or DMA requests to transfer data between the CPU and the serial
I/O ports.

14.2 FEATURES

The most important features of the S3C2500B High-Speed UART include:
•
Programmable baud rates
•
32-byte Transmit FIFO and 32-byte Receive FIFO
•
High-Speed UART source clock selectable (Internal clock: PCLK2, External clock: EXT_UCLK)
•
(PCLK2 = PCLK / 2)
•
Infra-red (IR) transmit/receive
•
Insertion of one or two Stop bits per frame
•
Selectable 5-bit, 6-bit, 7-bit, or 8-bit data transfers
•
Parity checking
SIO unit has a baud rate generator, transmitter, receiver, and a control unit, as shown in Figure 14-1. The baud-
rate generator can be driven by the internal system clock divided by 2, PCLK2, or by the external clock,
EXT_UCLK. Auto Baud Rate Generator tries to get the baud rate from input data in this mode. The transmitter
and receiver blocks have independent data buffer registers and data shifters. And 32-byte transmit FIFO and 32-
byte receive FIFO is also provided which include transmit and receive buffer.
In non-FIFO mode, transmit data is written first to the transmit buffer register. From there, it is copied to the
transmit shifter and then shifted out by the transmit data pin, HUTXD0/ HUTXD1. Receive data is shifted in by the
receive data pin, HURXD0/HURXD1. It is then copied from the shifter to the receive buffer register when one
data byte has been received.
Otherwise, you can select FIFO mode. In FIFO mode, transmitter and receiver use transmit FIFO and receive
FIFO, instead of Tx/Rx buffer register(HUTXBUF/HURXBUF). They are controlled by each FIFO trigger level.
The SIO control units provide software controls for mode selection, and for status and interrupt generation.
In S3C2500B, software flow control or hardware flow control can be selected according to the application.
SERIAL I/O (HIGH-SPEED UART)
SERIAL I/O (HIGH-SPEED UART)
14-1