
SIO
S3C3410X RISC MICROPROCESSOR
10-2
SIO FUNCTION DESCRIPTION
NON-DMA MODE OPERATION
Transmit and Receive By Synchronous Serial Line
The 8-bit data can be transmitted and received through SIO port. The serial output data can go out through a
serial output pin(SIOTXD), and the serial input data can come through a serial input pin(SIORXD). In this case,
the data should be sent and received synchronously by serial clock pin(SIOCLK). After transmitting or receiving
data, the SIO interrupt request will be activated if users enable an interrupt for SIO TX and RX. Because of the
separate hardware for TX and RX, the dual operation of TX and RX is possible. If users want to use the receiving
operation, users can treat the receive data as dummy one.
The TX and RX rate can be controlled by having the appropriate configuration in the SIOCON and SBRDR
registers. The clock source of serial interface can be an internal or external clock. In other words, the TX and RX
rate are programmable and users can determine the rate by having a suitable configuration in the SIOCON and
SBRDR registers.
Programming Procedure
When users write a byte data into the SIODAT register, the SIO will start to transmit a data if the SIO run bit is
set and the transmit mode bit is enabled.
To program the operation of SIO modules, please take following steps:
1.
Configure the multiplexed I/O pins as SIO related ones(SIOTXD, SIORXD, SIOCLK, and SIORDY).
2.
Configure the SIOCON register to have a necessary functionality of the serial I/O module.
3.
For the operation of interrupt mode in SIO, configure the interrupt mode in SIOCON register and enable
interrupt-relating bits in interrupt controller.
4.
In case of interrupt mode for TX, users should write a data to be transmitted in SIODAT, first. To start the
transmission, users should write SB(SIO Start) bit in SIOCON register. After transmission, there should be
SIO interrupt. In case of interrupt mode of RX, there will be SIO interrupt after receipt. To start the receiving
operation, users should write SB bit in SIOCON register.
5.
Go to step 4 if users need interrupt-based SIO operation more.