AD7490 Interfacing with Microcontroller

Thread Starter

elabsp

Joined Oct 23, 2013
13
Hi,

I am facing some problem in Reading Analogue values from AD7490. I always received FF from ADC. If any one interface this ADC with 8 bit Microcontroller then please share your experience.

Thanks
 

MrChips

Joined Oct 2, 2009
19,158
You will have to provide more information than that.
Which microcontroller are you using?
Show us your circuit schematic.
Show us your code.
 

Thread Starter

elabsp

Joined Oct 23, 2013
13
Thanks MrChips

I am using Microcontroller with 11.0592 MHz and connected with SPI pins I was confused due to arrangement of 12bit command word.
According to the datasheet 12bit command word with 12th bit MSB (write) and LSB is Coding bit. However We have 16 bit integer so I m confused that either I need to send 0x8330 command byte or 0x08333 command byte.
 

ErnieM

Joined Apr 24, 2011
7,991
You send the command byte as you receive the last conversion. The first 12 bits hold the config data, the last 4 bits are all "don't care."

And for a 16 bit conversion your received (incorrect) data should be 0xFFFF not just FF.
 

Thread Starter

elabsp

Joined Oct 23, 2013
13
Thanks issue is resolved. Problem is that I was not giving CS cycling after writing command byte.

Again thanks
 
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