27906 Parallax Inc, 27906 Datasheet - Page 5

• Manufacturer Part Number: 27906
• Description: BASIC STAMP ACT BOARD NO PWR
• Manufacturer: Parallax Inc

Specifications of 27906

• Module/board Type: Activity Board
• For Use With/related Products: BASIC Stamp®
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Interfacing with the HB-25 Motor Controller
The Position Controller is designed to be interfaced with an HB-25 motor controller to control the position
and speed of the motor and wheel. This can be accomplished by connecting a standard three-pin cable
from the header pins marked “To HB25” to the three-pin header on the HB-25. Be sure to connect each
end of the cable in the proper orientation of white “W”, red “R”, and black “B” as marked on both the
Position Controller and the HB-25. Connect the power leads on the HB-25 as usual (positive supply to
the “+” and ground to the “—”) and the DC brushed motor to M1 and M2 on the HB-25 respectfully.
Command Set Summary
The Position Controller’s command set is grouped by category as query commands, configuration
commands, and action commands.
Query commands request information from a specific individual
Position Controller board and generate a reply.
Action commands affect the output of the Position
Controller when it is being used to control an HB-25 motor controller, and do not generate a reply.
Configuration commands set certain parameters in one or more Position Controller boards and also do
not generate a reply. Any variables modified by configuration commands are reset to default when the
device loses power.
Command codes are byte-sized with the upper 5
Command Code Byte Example
bits containing the command value and the lower 3
0 0 1 0 1 0 0 1
bits containing the ID value of the device for which
the command is intended, minimizing the required
byte count for each command.
Command = CLRP
ID = 1
Depending on the command, a command code may require zero, one, or two additional bytes of data.
For commands which require two bytes of data, or commands which generate a reply, data is sent high
byte first, then low byte. The Command Set Details section below contains thorough information for each
command.
A Position Controller will accept a command if the ID value sent in the command code matches the
Position Controller’s own ID. Additionally, a Position Controller will also accept configuration commands
and action commands when the ID value is 0. This is a special case ID value which allows certain
commands to be sent to all devices present on the bus at once. Note that query commands do not
generate a response when the special case ID value of 0 is used, since doing so would likely cause bus
contention between devices.
Copyright © Parallax Inc.
Position Controller Kit (#27906)
v1.1 3/22/2010 Page 5 of 13