ADAQ4001: How to Write Register with 4-WIRE CS MODE?

Hi,

We will contact the product owner and get back to you.

Thanks,
Janine

Hi Shin,

Yes, it is possible to write registers, but you have to do it when the conversion is complete. 

In the 4-Wire CS Mode, SDI = HIGH during the rising edge of CNV. Please note that in this mode, the busy indicator is not used, thus, you must time out the maximum conversion time prior to readback. You will also have to rely solely on the SDI line to manage the communication. 

Then, once the conversion is done, you should pull down the SDI of the device that you want to write data from. 

Also, if you want to read or write the registers then you need to pull down CNV and write the correct register access command. With CNV low, the device can be programmed by clocking in a 16-bit word on SDI on the rising edge of SCK. Please refer to Figure 53 or Register Read and Write Functionality section of the datasheet for the timing diagram.

Let me know if this needs further clarification.

Thanks,
Chelsea

Hi Chelsea

I tried your suggestion.

However, I was unable to read the registers of the ADAQ4001. (Perhaps I might not have been able to write to them either.)

I am sending you the oscilloscope observation photos.

If this is not enough to understand the issue, please let me know what additional information you need.

Thanks,

Shin

Chelsea 

Hi,

No feedback on my photo?

To the untrained eye, it looks like something is slugging the SDO line.  It may be better to have a 1:1 discussion with your local ADI FAE to review your schematic for potential problems.

Hi Shin537 ,

Apologies for the delayed response. Can you also share what other devices the SDO line is connected with? I'm afraid that it is not properly pulled up/down, as mtfwalker  mentioned.

Do you also know if the SCK's 9^th bit is intentionally longer compared with the others during Register Read?

Thanks,
Chelsea