Matthew at 01:14, 5 September 2026

2026-09-05T01:14:25Z

← Older revision		Revision as of 01:14, 5 September 2026
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	The simulator's '''Indicators''' section has two lamps, '''LED1''' and '''LED2''', which		The simulator's '''Indicators''' section has two lamps, '''LED1''' and '''LED2''', which
	follow the registers <code>REG30</code> and <code>REG31</code> as your program runs. They		follow the registers <code>REG30</code> and <code>REG31</code> as your program runs. They
	give you a way to see a value you cannot hear — an envelope follower, a tempo, the state		give you a way to see a value you cannot hear while you are developing — an envelope
	of a switch.		follower, a tempo, the state of a switch.

	== How brightness is worked out ==		== How brightness is worked out ==
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	The scale is linear on purpose. A program that wants a curve is two instructions from the		The scale is linear on purpose. A program that wants a curve is two instructions from the
	curve it wants.		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 <code>REG30</code> or <code>REG31</code>. 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 ==		== Lighting a lamp ==

Matthew: Created page with "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 — an envelope follower, a tempo, the state of a switch. == How brightness is worked out == 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 signa..."

2026-09-05T01:04:29Z

Created page with "The simulator's '''Indicators''' section has two lamps, '''LED1''' and '''LED2''', which follow the registers <code>REG30</code> and <code>REG31</code> as your program runs. They give you a way to see a value you cannot hear — an envelope follower, a tempo, the state of a switch. == How brightness is worked out == 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 signa..."

New page

The simulator's '''Indicators''' section has two lamps, '''LED1''' and '''LED2''', which
follow the registers <code>REG30</code> and <code>REG31</code> as your program runs. They
give you a way to see a value you cannot hear — an envelope follower, a tempo, the state
of a switch.

== How brightness is worked out ==

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.

== Lighting a lamp ==

Write the value you want to see into <code>REG30</code> or <code>REG31</code>:

<pre>
; #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
</pre>

Without the <code>sof 0.5, 0.5</code> the lamp is dark for half of every LFO cycle.

== Naming the lamps ==

A comment tag renames a lamp in the panel:

<pre>
; #LED1 Tempo
</pre>

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 ==

Nothing on the FV-1 reserves <code>REG30</code> or <code>REG31</code>. 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.

== See also ==
* [[Using the FV-1 simulator]]
* [[Controlling the simulator with MIDI]]

[[Category:How-to]]

Using the simulator indicator lamps - Revision history

Matthew at 01:14, 5 September 2026