User’s Manual U13850EJ4V0UM
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CHAPTER 10 SERIAL INTERFACE FUNCTION
10.1 Overview
The V850/SB1 and V850/SB2 incorporate the following serial interfaces.
•
Channel 0: 3-wire serial I/O (CSI0)/I
2
C0
Note
•
Channel 1: 3-wire serial I/O (CSI1)/Asynchronous serial interface (UART0)
•
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: 8 to 16-bit variable-length 3-wire serial I/O (CSI4)
Note
I
2
C0 and I
2
C1 support Multimaster (
µ
PD70303xAY and 70F303wAY only).
Either 3-wire serial I/O or I
2
C can be used as a serial interface.
10.2 3-Wire Serial I/O (CSI0 to CSI3)
CSIn (n = 0 to 3) has the following two modes.
(1) Operation stop 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), serial output line (SOn), and
serial input line (SIn).
Since simultaneous transmit and receive operations are enabled 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.
3-wire serial I/O mode is useful for connection to a peripheral I/O device that includes a clocked serial interface,
a display controller, etc.