Numato_Oscillator Slow Square Wave Generator

By default this macro produces a 1 Hz square wave on Pin 0 of any Numato 8, 16, 32, or 64 USB device.

Note that it assumes you don't also have an Arduino simultaneously plugged into a USB port, since this macro just looks for the first supported device and presumes it's a Numato.

The output defaults to pin 0. The generated square wave will be 0 to +5 V on the Numato 8, while the others will be 0 to +3.3 V.

This is a simple way to get a calibrated AC voltage source for full-scale range calibration using the input voltage method. You can measure the power supply voltage (+5 or +3.3) with a DC meter, and be certain that the oscillator output will run between 0 and that value. Even if you don't have a meter, the voltage will be pretty close to the nominal value.

Numato_Oscillator Macro Listing:

;<Help=H492C

;Slow square or pulse LED flasher for Numato.
;Hit any key to stop.

H=0.5         ;High duration of wave/flash period, sec
L=H           ;Low duration (default 1 Hz square wave)

Posn#0=0               ;Numato08-64
Posn#1=0
@_ComDev_Scan       ;Scan COM devices, open port

UK=0
WHILE.UK=0             ;Loop until key found
    Port="gpio set 0"      ;Pin 0 high
    WaitSecs=H             ;Output HIGH duration
    Port="gpio clear 0"    ;Pin 0 low
    WaitSecs=L             ;Output LOW duration
    UK=Key?!               ;Get current key, if any
WEND.                  ;Back to test key

Port#O=0               ;Close port

See also Macro Examples and Mini-Apps, USB / Serial Communications Port Access