Accelerometer Example of New Crio

[Joe Ross]

There's updated files for the SPI ADXL345 example attached to the firstforge bug report. http://firstforge.wpi.edu/sf/go/artf1432

[NeatNit]

The fixed SPI example still doesn't work for me. I've finally gotten I2C working though, apparently it only works with the flat cable.

[jhersh]

Originally Posted by NeatNit

The fixed SPI example still doesn't work for me. I've finally gotten I2C working though, apparently it only works with the flat cable.

Not sure what "flat cable" you are talking about. If it is the DB-37 cable from the kit, then it "only works" if you fix the cable end to not be reversed.

[NeatNit]

Originally Posted by jhersh

Not sure what "flat cable" you are talking about. If it is the DB-37 cable from the kit, then it "only works" if you fix the cable end to not be reversed.

Yes, I meant that flat cable the replaced the thick round ones in previous years. What I meant to say is that the ADXL345 doesn't work with the old cable, in other words only works with the newer flat one. (our cable needed to be flipped but we already did that)

[jhersh]

Originally Posted by NeatNit

Yes, I meant that flat cable the replaced the thick round ones in previous years. What I meant to say is that the ADXL345 doesn't work with the old cable, in other words only works with the newer flat one. (our cable needed to be flipped but we already did that)

It works with my thick round one. Maybe yours is just damaged.

-Joe

[NeatNit]

Originally Posted by jhersh

It works with my thick round one. Maybe yours is just damaged.

-Joe

Taken from this thread: http://www.chiefdelphi.com/forums/sh...d.php?t=100324

Originally Posted by ggorsuch

Got it working!
Used the flat db37 cable included in this years Kop, instead of the old round one.

Originally Posted by abrightwell

That's what we just did and sure enough it worked. Makes sense as when we Ohm'ed it out, pin 1 went to pin 15 on the other end. I didn't think to check the KoP website, but I'm definitely going to check it out. It still seems like a curious situation that the flat works for the accelerometer but the round doesn't. :-/ Oh well, I'll take it at face value for now.

Thanks for the follow up!

Sure, these are Java, but I'm still seeing a recurring pattern....

[Gary Bonner]

My Labview Getting Started window does not list any tutorials. Can they be found anywhere else?

[Alan Anderson]

Originally Posted by Gary Bonner

My Labview Getting Started window does not list any tutorials.

It looks like you might not have installed the NI LabVIEW update linked from the Kit of Parts page.

[rwood359]

Originally Posted by jhersh

It works with my thick round one. Maybe yours is just damaged.

-Joe

We couldn't communicate on the I2C bus using the round cable. Switching to the flat cable fixed the problem.

[jhersh]

Originally Posted by rwood359

We couldn't communicate on the I2C bus using the round cable. Switching to the flat cable fixed the problem.

Good to know. Seems like there must have been a bad set of cables one of the previous years. I'm a little surprised that teams didn't complain about this in the year the bad cables were included. I guess no team tried to use I2C in that year. Given that this is the first year with a challenge that benefits from an accelerometer, I guess that makes sense.

-Joe

[zlong]

We also struggled with the ADXL345 in I2C mode. Running the included LabVIEW example the device worked intermittently. I looked at SDA and SCL with an O-Scope and noticed they where kind of floating when communication had error-ed out. My fix for this was to place a 100 ohm pull up resistor on both SDA and SCL. This made the ADXL345 perform wonderfully on the I2C bus. We have implemented this fix on our robot and so far have been very happy with the ADXL345's performance.

[Joe Ross]

Originally Posted by zlong

We also struggled with the ADXL345 in I2C mode. Running the included LabVIEW example the device worked intermittently. I looked at SDA and SCL with an O-Scope and noticed they where kind of floating when communication had error-ed out. My fix for this was to place a 100 ohm pull up resistor on both SDA and SCL. This made the ADXL345 perform wonderfully on the I2C bus. We have implemented this fix on our robot and so far have been very happy with the ADXL345's performance.

100 ohms seems like a lot for I2C to me. The [url=http://www.usfirst.org/sites/default/files/uploadedFiles/Robotics_Programs/FRC/Game_and_Season__Info/2012_Assets/Digital%20Sidecar.pdf]Digital Sidecar is supposed to have 3.16k on SDA and SCL. Can you check if those pullups are working?

[Joe Ross]

Originally Posted by jhersh

Not sure what "flat cable" you are talking about. If it is the DB-37 cable from the kit, then it "only works" if you fix the cable end to not be reversed.

Several people have reported it worked with the fixed cable in this year's kit, but not the DB37 from a previous year's kit.

Looking through previous year's KOP lists, it looks like there have been several sources. In 2009 and 2010, it was a cablestogo pn 02688. Last year it was SF Cable pn D720-03. Maybe one of these was missing a pin that related to I2C.