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accessing the Analog Devices ADIS16488 (IMU) and a Novatel GPS receiver — Parallax Forums

accessing the Analog Devices ADIS16488 (IMU) and a Novatel GPS receiver

jekain314jekain314 Posts: 3
edited 2012-05-04 13:34 in Propeller 1
I want to read a Analog Devices ADIS16488 Inertial Measurement Unit (yikes -- its $1600) from the Propellor.
This device has 3-axis accels, 3-axis gyros, 3-axis magnetometer and baro --- with an accuracy about as good as most military devices!
It produces an SPI output for its data and uses a number of discrete I/O poins as well.

Also, I will be using a OEMStar GPS receiver from Novatel.
This has TTL output as well as a USB.

The idea is to mathematically merge these two sensors and get the precision position as well as attitude to abopiut 0.1 deg.

I see the propellor has a natve SPI port - so the ADIS16488 may be staightforward.

I assume that the GPS receiver TTL stream can be used with one of the serisal data objects??

Any suggestions would be appreciated.

--- Jim.

Comments

  • Duane DegnDuane Degn Posts: 10,588
    edited 2012-05-04 13:25
    There are several GPS objects in the OBEX.

    I found several of them a bit awkward in the way they used serial objects.

    There's a four port serial object that is really useful in projects like these. Tracy Allen's version is the best IMO.

    When I was working on a GPS project I found the objects I looked at were using the older floating point objects. F32 is a newer floating point object that uses only one cog and is faster than the other versions.

    The Propeller doesn't really have native SPI (or anything else). All the ports are software defined. There are several SPI objects in the Propeller Tool library and the Prop can handle SPI just fine.
  • Mike GreenMike Green Posts: 23,101
    edited 2012-05-04 13:34
    All of the I/O you mentioned is handled via software in the Propeller and there is a variety of library routines in the Propeller Object Exchange. You might have a look at the 4-port serial driver there. You can use one port for the GPS and have a 2nd available for debugging if you want. In addition, this driver handles flow control and has a higher aggregate speed than the FullDuplexSerial driver. I think the best one is by Tracy Allen. There are several objects for handling SPI. A lot will depend on the specifics of the device you're using and the speed you want. You'll probably do best modifying an existing IMU driver
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