User’s Manual U15109EJ3V0UD
324
CHAPTER 11 SERIAL INTERFACE FUNCTION
11.1 Overview
The V850/SC1, V850/SC2, and V850/SC3 incorporate the following serial interfaces.
•
Channel 0: 3-wire serial I/O (CSI0)/I
2
C0
Note
•
Channel 2: 3-wire serial I/O (CSI2)/I
2
C1
Note
•
Channel 3: 3-wire serial I/O (CSI3)/asynchronous serial interface (UART1)
•
Channel 4: 3-wire serial I/O (CSI4)/asynchronous serial interface (UART0)
•
Channel 5: 3-wire serial I/O (CSI5)
•
Channel 6: 3-wire serial I/O (CSI6)
•
Channel 7: Asynchronous serial interface (UART2)
•
Channel 8: Asynchronous serial interface (UART3)
Note
I
2
C0 and I
2
C1 support multimasters.
Either 3-wire serial I/O or I
2
C can be used as a serial interface.
11.2 3-Wire Serial I/O (CSI0, CSI2, CSI3): 8 Bits
CSIn (n = 0, 2, 3) has the following two modes.
(1) Operation stopped mode
This mode is used when serial transfers are not performed.
(2) 3-wire serial I/O mode (fixed as MSB first)
This is an 8-bit data transfer mode using three lines: a serial clock line (SCKn), a serial output line (SOn), and a
serial input line (SIn).
Since data can be transmitted and received simultaneously in 3-wire serial I/O mode, the processing time for
data transfer is reduced.
The first bit in the 8-bit data in serial transfers is fixed as the MSB.
The SCK0 and SCK2 pins can be used to select normal output and N-ch open-drain output, respectively, by
setting the port 1 function register and port 2 function register (PF1, PF2).
3-wire serial I/O mode is useful for connection to devices such as peripheral I/O that include a clocked serial
interface, and display controllers.