MK 2 – Peripherals

Posted: 2010/09/18 in Uncategorized

The BeagleBoard performs most of the high level functions but also interfaces with peripheral processor for low-level real-time functions.

Three peripheral processors are used:

  1. a Phidget LCD processor, dedicated to displaying information sent to its USB port by the BeagleBoard.  This is really handy for debugging by providing progress marks of the main controller software.
  2. a second Phidget processor accessed via a second USB port of the BeagleBoard.  It is not programmable but provides a very nice set of libraries to interface 8 analogue input ports, 8 digital input ports and 8 digital output ports.  Its I/O port is reported back to the BeagleBoard as events that can be captured by the controlling software.  This Phidget is used to interface to the sonars, IRPDs, line detector, various touch sensors, power monitoring sensors, etc…
  3. For more real-time functions I opted for another 3rd processor, a BS2 SX basic stamp.  It interfaces with the BeagleBoard through an RS-232 port.  The BeagleBoard will send high level commands to the BS2 and the BS2 will return results back to the BB.  The really cool feature here is that I can program the BS2 from the BeagleBoard through the same RS-232 port used for communication.  So I can store the BS2 program on the BB and download it as part of the system initialization, therefore keeping the main brain and BS2 program versions in synch.  The BS2 will take care of interfacing with the motor control board, the PWM generator and rotation encoders monitoring the speed of the wheels.

You probably noticed by now that I really try to support Canadian vendors and companies in my product selections.


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