User’s Manual U14359EJ4V0UM
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CHAPTER 11 SERIAL INTERFACE FUNCTION
11.1 Features
The serial interface function provides two types of serial interfaces equipped with six transmit/receive channels of
which four channels can be used simultaneously.
The following two interface formats are available.
(1) Asynchronous serial interface (UART0 to UART2): 3 channels
(2) Clocked serial interface (CSI0 to CSI2): 3 channels
UART0 to UART2, which use the method of transmitting/receiving one byte of serial data following a start bit,
enable full-duplex communication to be performed.
CSI0 to CSI2 transfer data according to three types of signals (3-wire serial I/O). These signals are the serial clock
(SCK0 to SCK2), serial input (SI0 to SI2), and serial output (SO0 to SO2) signals.
11.1.1 Switching between UART and CSI modes
In the V850E/MA1, since UART0 and CSI0 pin and the UART1 and CSI1 pin are alternate function pins, they
cannot be used at the same time. The PMC4 and PFC4 registers must be set in advance (see
14.3.5 Port 4
).
Also, since UART2 and CSI2 have alternate functions as external interrupt request input pins (INTP120 and
INTP130 to INTP133), the PMC3 and PFC3 registers must be set in advance (see
14.3.4 Port 3
).
If the mode is switched during a transmit or receive operation in UARTn or CSIn, operation cannot be guaranteed.
