Page 176 - The Unofficial Guide to Lego Mindstorms Robots

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.StartTask 2
.EndOfTask
.BeginOfTask 1
.While 0, 0, 2, 0, 0
.PlayTone 392, 10
.PlayTone 523, 10
.PlayTone 659, 10
.PlayTone 784, 20
.PlayTone 659, 10
.PlayTone 784, 20
.Wait 2, 80
.Wait 2, 80
.EndWhile
.EndOfTask
.BeginOfTas k 2
.On "02"
.While 0, 0, 2, 0, 0
.SetFwd "02"
.Wait 2, 50
.SetRwd "02"
.Wait 2, 50
.EndWhile
.EndOfTa sk
Pause 5
.CloseComm
End With
End Sub

Tasks 1 and 2 both use While and EndW hile to loop forever. Task 1 plays a song over and over, while task 2 runs the
outputs in forward and reverse.

Tips

You've already seen a lot of the functionality of Spiri t.ocx exposed in NQC. Although the syntax in Visual Basic is different,
the basic functions are the sam e. LEGO's official Tech nical Reference Document (see the ''Online Resources") does a good job
describing the syntax of Spirit. ocx commands; I won't attempt to duplicate that work. Instead, this section contains down-to-
earth information on using Spirit.ocx.

Retrieving Input and Timer Values

Although the Technical Referenc e Document makes it clear how to reset timer values and how to configure the RCX's inputs,
you may be left wonder ing how to retrieve the value of an input or timer. The answer is a versatile function called Poll.
Poll can return many val ues from the RCX, including input values (in several different forms), timer values, variable values,
C
the curr ent status of the R X's outputs, an d the last value received over the IR port.