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3-WIRE SERIAL DATA BUS

The 3-wire communication mode operates similar to the SPI mode. However, in 3-wire mode, there is

one bi-directional I/O instead of separate data in and data out signals. The 3-wire consists of the I/O (SDI

and SDO pins tied together), CE, and SCLK pins. In 3-wire mode, each byte is shifted in LSB first

unlike SPI mode where each byte is shifted in MSB first. As is the case with the SPI mode, an address

byte is written to the device followed by a single data byte or multiple data bytes. Figure 7 illustrates a

read and write cycle. Figure 8 illustrates a multiple byte burst transfer. In 3-wire mode, data is input on

the rising edge of SCLK and output on the falling edge of SCLK.

3-WIRE SINGLE BYTE TRANSFER

Figure 7

3-WIRE MULTIPLE BYTE BURST TRANSFER Figure 8