neopixel: Add support for delaying updates in SET_LED command

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

docs/G-Codes.md

@@ -222,13 +222,16 @@ is enabled:
 
 The following command is available when "neopixel" or "dotstar" config
 sections are enabled:
-- `SET_LED LED=<config_name> INDEX=<index> RED=<value> GREEN=<value>
-  BLUE=<value>`: This sets the LED output. Each color <value> must be
-  between 0.0 and 1.0. If multiple LED chips are daisy-chained then
-  one may specify INDEX to alter the color of just the given chip (1
-  for the first chip, 2 for the second, etc.). If INDEX is not
-  provided then all LEDs in the daisy-chain will be set to the
-  provided color.
+- `SET_LED LED=<config_name> RED=<value> GREEN=<value> BLUE=<value>
+  [INDEX=<index>] [TRANSMIT=0]`: This sets the LED output. Each color
+  <value> must be between 0.0 and 1.0. If multiple LED chips are
+  daisy-chained then one may specify INDEX to alter the color of just
+  the given chip (1 for the first chip, 2 for the second, etc.). If
+  INDEX is not provided then all LEDs in the daisy-chain will be set
+  to the provided color. If TRANSMIT=0 is specified then the color
+  change will only be made on the next SET_LED command that does not
+  specify TRANSMIT=0; this may be useful in combination with the INDEX
+  parameter to batch multiple updates in a daisy-chain.
 
 ## Servo Commands
 

klippy/extras/dotstar.py

@@ -48,6 +48,7 @@ class PrinterDotstar:
         red = self.gcode.get_float('RED', params, 0., minval=0., maxval=1.)
         green = self.gcode.get_float('GREEN', params, 0., minval=0., maxval=1.)
         blue = self.gcode.get_float('BLUE', params, 0., minval=0., maxval=1.)
+        transmit = self.gcode.get_int('TRANSMIT', params, 1)
         red = int(red * 255. + .5)
         blue = int(blue * 255. + .5)
         green = int(green * 255. + .5)
@@ -59,6 +60,8 @@ class PrinterDotstar:
         else:
             self.color_data[4:-4] = color_data * self.chain_count
         # Send command
+        if not transmit:
+            return
         print_time = self.printer.lookup_object('toolhead').get_last_move_time()
         self.send_data(self.spi.get_mcu().print_time_to_clock(print_time))
 

klippy/extras/neopixel.py

@@ -60,8 +60,11 @@ class PrinterNeoPixel:
         blue = self.gcode.get_float('BLUE', params, 0., minval=0., maxval=1.)
         index = self.gcode.get_int('INDEX', params, None,
                                    minval=1, maxval=self.chain_count)
+        transmit = self.gcode.get_int('TRANSMIT', params, 1)
         self.update_color_data(red, green, blue, index)
         # Send command
+        if not transmit:
+            return
         print_time = self.printer.lookup_object('toolhead').get_last_move_time()
         self.send_data(self.mcu.print_time_to_clock(print_time))