CHAPTER 16 ASYNCHRONOUS SERIAL INTERFACE/3-WIRE SERIAL I/O
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16.4 3-Wire Serial I/O Mode
This mode is used to perform 8-bit data transfer with the serial clock (SCK1, SCK2), serial output (SO1, SO2),
and serial input (SI1, SI2) lines.
The 3-wire serial I/O mode supports simultaneous transmit/receive operation, thereby reducing the data transfer
processing time.
The start bit of 8-bit data for serial transfer is fixed as the MSB.
The 3-wire serial I/O mode is effective when connecting a peripheral I/O with an on-chip clock synchronization
serial interface, a display controller, etc.
16.4.1 Configuration
The 3-wire serial I/O mode includes the following hardware.
Figure 16-11 shows the block diagram for the 3-wire serial I/O mode.
Table 16-5. 3-Wire Serial I/O Configuration
Item
Configuration
Registers
Serial I/O shift registers 1, 2 (SIO1, SIO2)
Control registers
Serial operation mode registers 1, 2 (CSIM1, CSIM2)
