Samsung C8249, P8245, P8249, S3C8245 user manual 16

S3C8245/P8245/C8249/P8249 SERIAL I/O INTERFACE
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16 SERIAL I/O INTERFACE
OVERVIEW
Serial I/O module, SIO can interface with various types of external device that require serial data transfer. The
components of each SIO function block are:
—8-bit control register (SIOCON)
—Clock selector logic
—8-bit data buffer (SIODATA)
—8-bit prescaler (SIOPS)
—3-bit serial clock counter
—Serial data I/O pins (SI, SO)
—External clock input/output pins (SCK)
The SIO module can transmit or receive 8-bit serial data at a frequency determined by its corresponding control
register settings. To ensure flexible data transmission rates, you can select an internal or external clock source.
PROGRAMMING PROCEDURE
To program the SIO modules, follow these basic steps:
1. Configure the I/O pins at port (SO, SCK, SI) by loading the appropriate value to the P1CONH register if
necessary.
2. Load an 8-bit value to the SIOCON control register to properly configure the serial I/O module. In this operation,
SIOCON.2 must be set to "1" to enable the data shifter.
3. For interrupt generation, set the serial I/O interrupt enable bit (SIOCON.1) to "1".
4. When you transmit data to the serial buffer, write data to SIODATA and set SIOCON.3 to 1, the shift operation
starts.
5. When the shift operation (transmit/receive) is completed, the SIO pending bit (SIOCON.0) is set to "1" and an
SIO interrupt request is generated.