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AS8650B

Datasheet - Application In form atio n

8.1.1 SPI Write Operation

The SPI write operation begins with clock polarity selection at negative edge of CS, given in Table 20. Once the clock polarity is selected the SPI

write command is given by providing ‘0’ in R/W bit of the header field in first sampling edge at SDI pin. The 5 bits address of register to be written

is provided at SDI pin in next five consecutive sampling edges of SCLK. The first 2 bits in header fields are reserved and set to ‘0’. The data to be

written is followed by last bit of header field. With each sampling edge a bit is sampled starting from MSB to LSB. During complete SPI write

operation the CS has to be ‘low’. The SPI write operation ends with positive edge of CS. The wave form for SPI write operation with single data

byte is shown in Figure 16 and Figure 17.

Figure 16. SPI Write Operation with Negative Clock Polarity and 1 Byte of Data Field

Figure 17. SPI Write Operation with Positive Clock Polarity and 1 Byte of Data Field

R1

R0

A4

A3

A2

A1

A0

D7

D6

D5

D4

D3

D2

D1

D0

SCLK

SDI

SDO

CS

Sampling Edge

High Impedance Sate

SCLK

SDI

SDO

CS

R1

R0

A4

A3

A2

A1

A0

D7

D6

D5

D4

D3

D2

D1

D0

Sampling Edge

High Impedance Sate