labsw/tool/: basic labsw control utility

labsw/tool/README

@@ -0,0 +1,42 @@
+Lab Switch control utility
+--------------------------
+
+If invoked without arguments, labsw prints the firmware version and
+build date.
+
+The following commands can be given on the command line:
+
+ch1=0, ch1=1, ch2=0, ch2=1
+	turn the respective channel on or off. Both relay and
+	opto-coupler are switched. Also enters remote mode.
+
+query
+	read the buttons and opto-coupler inputs (rear panel)
+
+local
+	exit remote mode
+
+The Lab Switch starts in local mode, where the CH1/CH2 buttons
+toggle the respective channel. The main button turns off both
+channels. Local mode is indicated by a green main LED.
+
+If a channel is set via USB, the Lab Switch enters remote mode,
+indicated by a red main LED. In remote mode, the channel buttons
+are ignored. Pressing the main button exits remote mode and
+turns both channels off.
+
+The lab switch utility currently lacks the following features:
+- access to the rear opto-coupler outputs,
+- switching CH1/CH2 relay and opto-coupler independently,
+- direct control of LEDs.
+
+Examples:
+
+# labsw ch1=1
+
+Turns channel 1 on and enters remote mode.
+
+# labsw ch1=0 ch2=0 local
+
+Turns channels 1 and 2 off and exits remote mode. This is
+equivalent to pressing the main button.