FlexRIO FPGA, NI5782 ADC, DAC and Clock Chip configuration using SPI

[RaviMasand]

Hi,

I'm running a NI 5782 Analog I/O board on a PXIE 7976R Flex RIO FPGA module. The 5782 had on it a ADC, a DAC and a clock chip all controlled via a SPI bus. I need to access the registers in these devices to modify the default configuration at run-time. The CLIP provides primitives called 'SPI IDLE', 'SPI DEVICE', 'SPI ADDRESS' and so on. I suspect I have to drive these primitives with data from the device datasheets to modify the device configuration. However, I have been unable to find any documentation and/or examples to do this, Has anyone done this or can point me to some resource which answers this question? Thank You.

Ravi

[[dk]]

I would recommend looking at the NI FlexRIO Help and specifically at the NI 5782 Component-Level IP Reference. It contains documentation and descriptions of all of the CLIP I/O signals.

[RaviMasand]

Hi Daniel K,

This really helps. I can talk to the Analog Output (DAC 5682Z) device over SPI using this clip. However the document does NOT give the device number for the Analog Input device (ADS62P49). Hence am unable to talk to it. Tried some nearby device numbers (0,7, 😎 but met with no success. Any help appreciated. Thanks.

[David-A]

What are you trying to do with the ADC? If you want to adjust the offset thats what the bias DACs are for. 

[RaviMasand]

Hi Daniel K,

I need to turn on test patterns, change mode to offset binary (from 2's complement) and probably a few other things. The document says, all over, that it should be possible to access the ADCs registers via SPI.

Also, where are the BIAS DACs described?

Thanks for your help.

Ravi

[David-A]

In the CLIP help the SPI Device Select mentions bias DACs. 

Are you sure that a value of 0 for the SPI Device Select doesn't access the ADC? I haven't tried it but i check some register maps quick and I thought that was it. 

[RaviMasand]

Thats what I thought too. I tested it some, with no success. Will test some more.

Ravi

[RaviMasand]

Building a slightly more complicated project to test that. 

(Sorry David A, thought you were Daniel K)

[villanul]

Hi, I am in the same situation right now (with the exact same system), and all i want do is remove the DC offsets from the Analog input of the clip. Has anyone been able to do this?

It seems the bias DACS are adding an offset to my measured signal. 

kind regards,

Lorenzo