Using the simulator indicator lamps
The simulator's Indicators section has two lamps, LED1 and LED2, which
follow the registers REG30 and REG31 as your program runs. They
give you a way to see a value you cannot hear while you are developing — an envelope
follower, a tempo, the state of a switch.
How brightness is worked out[edit | edit source]
The lamp reads its register as S1.23:
- 0 is off.
- 1.0 is full brightness.
- A negative value is off. It is not rectified, so a bipolar signal lights the lamp only
on its positive half.
The scale is linear on purpose. A program that wants a curve is two instructions from the curve it wants.
The FV-1 has no LEDs. The lamps exist in the simulator only — nothing lights up on
the pedal when your program writes to REG30 or REG31. They are a
debugging aid for the time you spend writing code, not an output you can ship. A design
that needs an indicator on the finished pedal needs one built into the hardware.
Lighting a lamp[edit | edit source]
Write the value you want to see into REG30 or REG31:
; #LED1 Rate skp run, loop wlds sin0, 12, 32767 loop: cho rdal, sin0 ; bipolar, -1 to +1 sof 0.5, 0.5 ; fold to 0..1 so the lamp follows the whole cycle wrax reg30, 0
Without the sof 0.5, 0.5 the lamp is dark for half of every LFO cycle.
Naming the lamps[edit | edit source]
A comment tag renames a lamp in the panel:
; #LED1 Tempo
The tag is read from the comment part of the line, so it never collides with code. It is the same mechanism that names the pots — see Labelling pots and lamps in your source.
A gotcha[edit | edit source]
Nothing on the FV-1 reserves REG30 or REG31. A program that parks
scratch values there will light the lamps by accident. If a lamp flickers for no reason you
can explain, check whether those two registers are being used as general-purpose storage.