Datasheet

AD7760

Rev. A | Page 23 of 36

WRITING TO THE AD7760

There are many features and parameters that the user can

change by writing to the AD7760 device. See the

Using the

AD7760

section, which details the writing sequence needed to

initialize the operation of the part.

The AD7760 has programmable registers that are 16 bits wide.

This means that two write operations are required to program a

second write contains the register data. An exception is when a

user-defined filter is being downloaded to the AD7760. This is

described in detail in the

Downloading a User-Defined Filter

section. The

AD7760 Registers section contains the register

addresses and details.

Figure 3 shows a write operation to the AD7760. The

/WR

line is held high while the

line is brought low for a minimum

of four ICLK periods. The register address is latched during this

period. The

line is brought high again for a minimum of

four ICLK periods before the register data is put onto the data

bus. If a read operation occurs between the writing of the

cleared and the next write must be the register address. This

also provides a method to revert back to a known situation if

the user forgets whether the next write is an address or data.

Generally, the AD7760 is written to and configured on power-

up and very infrequently, if at all, after that. Following any write

operation, the full group delay of the filter must elapse before

valid data is output from the AD7760.