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SbRio-9636 how to increase DIO to 37 pins

NI

 

I am working with the SBrio-9636 kit in the CRIO evaluation kit, and am liking the board quite a bit.  

 

Running into a little problem though. I have  a design that I wanted to try on the SBrio that requires around  38 dio pins.  The board has only 28 pins. What are my options for increasing the DIO pins?

 

Paul

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Paul,

 

I am glad to hear that you are liking the sbRIO-9636! I would recommend going with an sbRIO that has an RIO Mezzanine Card (RMC) connector such as the sbRIO-9605, 9606, 9623, or 9626. The RMC connector allows you access to an additional 96 DIO lines.

 

Page 4 of this document has a high-level feature overview and comparison between the different sbRIOs.

Tannerite
National Instruments
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A caveat: the DIO on the RMC are slower than those on the board itself. The 9636 has 28 onboard DIO, which means they're nice and quick.

 

For other boards, I believe the 96 channels on the RMC are just the remaining 24 lines multiplexed x4, and as a result are a little slower.

 

Also, I could be wrong but I have a sneaking suspicion that channels on the RMC are not 5V tolerant input, whereas those on the board most definitely are. I can't remember where that's from, however...probably the specifications.

 

(I love my 9636s by the way! So much so that when I ran into a channel count issue, I decided to consolidate digital signals back down to what I actually needed, and still have spare!)

---
CLA
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thoult

 

 

Thanks for the nice response.

 

 

I was thinking to use a I2C module to extend the number of Io. Found a device that had 40 pins of io with good io drive current as well as voltage tolerances.  I just have to get the i2C library actually working.

 

Paul

This the chip I am thinking of using.

 

PCA9506DGG,518  pretty cheap at digikey.

 

will also be purchasing a breakout board. Found one for  under $10.

 

 

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thoult

 

 

Thanks for the nice response.

 

 

I was thinking to use a I2C module to extend the number of Io. Found a device that had 40 pins of io with good io drive current as well as voltage tolerances.  I just have to get the i2C library actually working.

 

Paul

This the chip I am thinking of using.

 

PCA9506DGG,518  pretty cheap at digikey.

 

will also be purchasing a breakout board. Found one for  under $10.

 

 

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I wanted to clarify a point in the previous post.  

 

The DIO lines on the RMC are not 'slower' than the sbRIO-9636 DIO lines.  The 96 lines on the RMC connector are connected to dedicated pins on the FPGA - no multiplexing is involved.  The primary difference between the 28 DIO on sbRIO-9636 and the RMC are outlines in the manual on page 31, specifically figures 19 and 20.  

 

sbRIO-9605/06/23/26/33/36 User Manual

 

Specifically, the 28 DIO on J502 and J503 have a bus switch that makes them 5V tolerant.  The RMC DIO lines are connected only through a series termination resistor.  

 

The reason the sbRIO-9626 doesn't have both the RMC DIO lines and 24 lines on J502 is the FPGA didn't have enough IO pins available to support both connectors populated at the same time.

 

Regards,

Spex
National Instruments

To the pessimist, the glass is half empty; to the optimist, the glass is half full; to the engineer, the glass is twice as big as it needs to be has a 2x safety factor...
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