View Single Post
  #2   Spotlight this post!  
Unread 01-02-2014, 16:14
Joe Hershberger Joe Hershberger is offline
National Instruments
AKA: jhersh
FRC #2468 (Appreciate)
Team Role: Mentor
 
Join Date: Nov 2005
Rookie Year: 1997
Location: Austin, TX
Posts: 148
Joe Hershberger is a name known to allJoe Hershberger is a name known to allJoe Hershberger is a name known to allJoe Hershberger is a name known to allJoe Hershberger is a name known to allJoe Hershberger is a name known to all
Re: I2C SRF02 Ultrasonic 7bit versus 8bit question

Quote:
Originally Posted by riftware View Post
1: 0x70 on the PI's i2c bus would be addressed as E0 on the crio due to the need to bit shift 1 left correct?
Correct.

Quote:
Originally Posted by riftware View Post
2: Do I only need to worry about that on the address of the device? OR do I need to perform a similar operation on the command register which sends a ping?
No... Only the device address is 7-bit. All others are simply 8-bit.

Quote:
Originally Posted by riftware View Post
3: Do I need to do the revers of that on values I retrieve from the device once I get the data back on the cRio?
No. Since all others are 8-bit, just use them.

Quote:
Originally Posted by riftware View Post
I2c work fine on my PI and my arduino but have been kind of crappy on the CRio. One other tidbit that may be effecting that is in reviewing the specs on the sidecar it looks like they already have pullup resistors on the i2c port where I've been putting them on my sensor spoke probably unecessarily. We were looking at 4 ultrasonics (collision avoidance) and the accelerometer on the i2c bus so we have a single hub that they all connect to.

Any insight is appreciated!
You do not need additional pull-ups.

One other think you should do is ensure that "compatability mode" is enabled.
Reply With Quote