Datasheet

78K0/Ix2 CHAPTER 16 SERIAL INTERFACE CSI11
R01UH0010EJ0500 Rev.5.00 556
Feb 28, 2012
16.4.2 3-wire serial I/O mode
The 3-wire serial I/O mode is used for connecting peripheral ICs and display controllers with a clocked serial interface.
In this mode, communication is executed by using three lines: the serial clock (SCK11), serial output (SO11), and
serial input (SI11) lines.
(1) Registers used
Serial operation mode register 11 (CSIM11)
Serial clock selection register 11 (CSIC11)
Port mode register 0 and 3 (PM0, PM3)
Port register 3 (P3)
The basic procedure of setting an operation in the 3-wire serial I/O mode is as follows.
<1> Set the CSIC11 register (refer to Figure 16-3).
<2> Set bits 4 to 6 (DIR11, SSE11, and TRMD11) of the CSIM11 register (refer to Figure 16-2).
<3> Set bit 7 (CSIE11) of the CSIM11 register to 1. Transmission/reception is enabled.
<4> Write data to transmit buffer register 11 (SOTB11). Data transmission/reception is started.
Read data from serial I/O shift register 11 (SIO11). Data reception is started.
Caution Take relationship with the other party of communication when setting the port mode register and
port register.