display: Add initial support for LCD screens attached to an MCU

Add support for displaying basic status information on ST7920 and
HD44780 based LCDs that are attached directly to a micro-controller.

Signed-off-by: Marcio Teixeira <marcio@alephobjects.com>
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

config/example-extras.cfg

@@ -345,6 +345,29 @@
 #   be provided.
 
 
+# Support for a display attached to the micro-controller.
+#[display]
+#lcd_type:
+#    The type of LCD chip in use. This may be either "hd44780" (which
+#    is used in "RepRapDiscount 2004 Smart Controller" type displays)
+#    or "st7920" (which is used in "RepRapDiscount 12864 Full Graphic
+#    Smart Controller" type displays). This parameter must be
+#    provided.
+#rs_pin:
+#e_pin:
+#d4_pin:
+#d5_pin:
+#d6_pin:
+#d7_pin:
+#    The pins connected to an hd44780 type lcd. These parameters must
+#    be provided when using an hd44780 display.
+#cs_pin:
+#sclk_pin:
+#sid_pin:
+#    The pins connected to an st7920 type lcd. These parameters must
+#    be provided when using an st7920 display.
+
+
 # Replicape support - see the generic-replicape.cfg file for further
 # details.
 #[replicape]

config/generic-rambo.cfg

@@ -107,3 +107,20 @@ pins:
 
 [static_digital_output yellow_led]
 pins: !PB7
+
+# "RepRapDiscount 2004 Smart Controller" type displays
+#[display]
+#lcd_type: hd47780
+#rs_pin: PG4
+#e_pin: PG3
+#d4_pin: PJ2
+#d5_pin: PJ3
+#d6_pin: PJ7
+#d7_pin: PJ4
+
+# "RepRapDiscount 128x64 Full Graphic Smart Controller" type displays
+#[display]
+#lcd_type: st7920
+#cs_pin: PG4
+#sclk_pin: PJ2
+#sid_pin: PG3

config/generic-ramps.cfg

@@ -82,3 +82,20 @@ max_velocity: 300
 max_accel: 3000
 max_z_velocity: 5
 max_z_accel: 100
+
+# "RepRapDiscount 2004 Smart Controller" type displays
+#[display]
+#lcd_type: hd47780
+#rs_pin: ar16
+#e_pin: ar17
+#d4_pin: ar23
+#d5_pin: ar25
+#d6_pin: ar27
+#d7_pin: ar29
+
+# "RepRapDiscount 128x64 Full Graphic Smart Controller" type displays
+#[display]
+#lcd_type: st7920
+#cs_pin: ar16
+#sclk_pin: ar23
+#sid_pin: ar17

config/printer-lulzbot-taz6-2017.cfg

@@ -108,3 +108,9 @@ pins:
 
 [static_digital_output yellow_led]
 pins: !PB7
+
+[display]
+lcd_type: st7920
+cs_pin: PG4
+sclk_pin: PJ2
+sid_pin: PG3