AD7738 Figure 10 and Figure 12 (Datasheet Rev. 0)

Document created by analog-archivist Employee on Feb 23, 2016
Version 1Show Document
  • View in full screen mode

We would like read two channels: Ain0-Ain1 and Ain2-Ain3, Continous Conversion,
RDYFN = 1. Figure 10 (AD7738 datasheet Rev.0) shows this example, but it is not
described in the datasheet how to set it up. Can you confirm the sequence for
Figure 10?

Also, can you confirm if Figure 12 is correct?


(i) Regarding Figure 10, the value to be written to the channel setup registers
should be 0x68 or 0x6C. Additionally, you need to set the RDYFN bit in the IO
Port Register by writing 0x38 to it.

(ii) Figure 12 provides continuous convert and continuous read and the
datasheet is incorrect and it should be setup as follows:

1. Write 0x38 (write to comms reg to setup write to mode reg)
2. Write 0x2C (write to mode reg to set continous conversion, dump mode and
cont rd.)
3. Write 0x48 (write to comms reg to setup read from data reg)
4. Read Data

It should also be possible to set the RDYFN bit when operating in continuous
read mode such that the RDY pin will go low only once all enabled channels have
new conversion results available.