AD7328

Rev. A | Page 21 of 36

REGISTERS

The AD7328 has four programmable registers: the control register, sequence register, Range Register 1, and Range Register 2. These

registers are write-only registers.

ADDRESSING REGISTERS

A serial transfer on the AD7328 consists of 16 SCLK cycles. The three MSBs on the DIN line during the 16 SCLK transfer are decoded to

determine which register is addressed. The three MSBs consist of the write bit, Register Select 1 bit, and Register Select 2 bit. The register

select bits are used to determine which of the four on-board registers is selected. The write bit determines if the data on the DIN line

following the register select bits loads into the addressed register. If the write bit is 1, the bits load into the register addressed by the

register select bits. If the write bit is 0, the data on the DIN line does not load into any register.

Table 8. Decoding Register Select Bits and Write Bit

Write

Register Select 1

Register Select 2

Description

0

0

0

Data on the DIN line during this serial transfer is ignored.

1

0

0

This combination selects the control register. The subsequent 12 bits are loaded into

the control register.

1

0

1

This combination selects Range Register 1. The subsequent 8 bits are loaded into

Range Register 1.

1

1

0

This combination selects Range Register 2. The subsequent 8 bits are loaded into

Range Register 2.

1

1

1

This combination selects the sequence register. The subsequent 8 bits are loaded into

the sequence register.