config: sample-macros.cfg creation and M300

Implementation of M300 "Play Tone"

Signed-off-by: Nicolas Dupont <ndupont@ndupont.net>
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

config/sample-macros.cfg

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+# This file provides examples of Klipper G-Code macros.  The snippets
+# in this file may be copied into the main printer.cfg file.
+#
+# See the "example.cfg" file for description of common config parameters.
+
+
+# M300 : Play tone, Beeper support, as commonly found on usual LCD displays
+# i.e. RepRapDiscount 2004 Smart Controller, RepRapDiscount 12864 Full Graphic
+# This defines a custom I/O pin and a custom GCODE macro
+# Usage: M300 [P<ms>] [S<Hz>]      P is the tone duration, S the tone frequency.
+# as it is based on a PWM duty cycle, the frequency won't be pitch perfect.
+#
+#[output_pin BEEPER_pin]
+#pin: ar37
+#   Beeper pin. This parameter must be provided.
+#   ar37 is the default RAMPS/MKS pin.
+#pwm: True
+#   A piezo beeper needs a PWM signal, a DC buzzer doesn't.
+#value: 0
+#   Silent at power on, set to 1 if active low.
+#shutdown_value: 0
+#   Disable at emergency shutdown (no PWM would be available anyway).
+#cycle_time: 0.001
+#   PWM frequency : 0.001 = 1ms will give a base tone of 1kHz
+#scale: 1000
+#   PWM parameter will be in the range of (0-1000 Hz).
+#   Although not pitch perfect.
+#
+#[gcode_macro M300]
+#default_parameter_S=1000
+#   Allows for a default 1kHz tone if S is omitted
+#default_parameter_P=100
+#   Allows for a default 10ms duration is P is omitted
+#gcode:  SET_PIN PIN=BEEPER_pin VALUE={S}
+#        G4 P{P}
+#        SET_PIN PIN=BEEPER_pin VALUE=0