KS57C2308/P2308/C2316/P2316 SERIAL I/O INTERFACE
13-1
13 SERIAL I/O INTERFACE
OVERVIEW
The serial I/O interface (SIO) has the following functional components:
—8-bit mode register (SMOD)
—Clock selector circuit
—8-bit buffer register (SBUF)
—3-bit serial clock counter
Using the serial I/O interface, 8-bit data can be exchanged with an external device. The transmission frequency
is controlled by making the appropriate bit settings to the SMOD register.
The serial interface can run off an internal or an external clock source, or the TOL0 signal that is generated by
the 8-bit timer/counter, TC0. If the TOL0 clock signal is used, you can modify its frequency to adjust the serial
data transmission rate.
SERIAL I/O OPERATION SEQUENCE
The general operation sequence of the serial I/O interface can be summarized as follows:
1. Set SIO mode to transmit-and-receive or to receive-only.
2. Select MSB-first or LSB-first transmission mode.
3. Set the SCK clock signal in the mode register, SMOD.
4. Set SIO interrupt enable flag (IES) to "1".
5. Initiate SIO transmission by setting bit 3 of the SMOD to "1".
6. When the SIO operation is complete, IRQS flag is set and an interrupt is generated.