uc1701: Add support for SSD1306 displays

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

config/example-extras.cfg

@@ -863,11 +863,12 @@
 # Support for a display attached to the micro-controller.
 #[display]
 #lcd_type:
-#   The type of LCD chip in use. This may be "hd44780" (which is
-#   used in "RepRapDiscount 2004 Smart Controller" type displays),
-#   "st7920" (which is used in "RepRapDiscount 12864 Full Graphic
-#   Smart Controller" type displays) or "uc1701" (which is used in
-#   "MKS Mini 12864" type displays). This parameter must be provided.
+#   The type of LCD chip in use. This may be "hd44780" (which is used
+#   in "RepRapDiscount 2004 Smart Controller" type displays), "st7920"
+#   (which is used in "RepRapDiscount 12864 Full Graphic Smart
+#   Controller" type displays), "uc1701" (which is used in "MKS Mini
+#   12864" type displays), or "ssd1306". This parameter must be
+#   provided.
 #rs_pin:
 #e_pin:
 #d4_pin:
@@ -885,6 +886,10 @@
 #a0_pin
 #   The pins connected to an uc1701 type lcd. These parameters must be
 #   provided when using an uc1701 display.
+#cs_pin:
+#dc_pin
+#   The pins connected to an ssd1306 type lcd. These parameters must
+#   be provided when using an ssd1306 display.
 #menu_root:
 #   Entry point for menu, root menu container name. If this parameter
 #   is not provided then default menu root is used. When provided

klippy/extras/display/display.py

@@ -11,7 +11,7 @@ import menu
 
 LCD_chips = {
     'st7920': st7920.ST7920, 'hd44780': hd44780.HD44780,
-    'uc1701' : uc1701.UC1701
+    'uc1701' : uc1701.UC1701, 'ssd1306': uc1701.SSD1306,
 }
 M73_TIMEOUT = 5.
 

klippy/extras/display/uc1701.py

@@ -12,6 +12,7 @@ BACKGROUND_PRIORITY_CLOCK = 0x7fffffff00000000
 TextGlyphs = { 'right_arrow': '\x1a', 'degrees': '\xf8' }
 
 class UC1701:
+    DATA_PIN_NAME = "a0_pin"
     CURRENT_BUF, OLD_BUF = 0, 1
     EMPTY_CHAR = (0, 32, 255)
     def __init__(self, config):
@@ -20,7 +21,7 @@ class UC1701:
         mcu = self.spi.get_mcu()
         # Create a0 pin
         ppins = config.get_printer().lookup_object('pins')
-        a0_pin_params = ppins.lookup_pin(config.get('a0_pin'))
+        a0_pin_params = ppins.lookup_pin(config.get(self.DATA_PIN_NAME))
         if a0_pin_params['chip'] != mcu:
             raise ppins.error("uc1701 all pins must be on same mcu")
         self.a0_oid = mcu.create_oid()
@@ -158,3 +159,29 @@ class UC1701:
             page[:] = zeros
     def get_dimensions(self):
         return (16, 4)
+
+# The SSD1306 (in 4-wire SPI mode) differs from UC1701 only in display init
+class SSD1306(UC1701):
+    DATA_PIN_NAME = "dc_pin"
+    def init(self):
+        init_cmds = [
+            0xAE,       # Display off
+            0xD5, 0x80, # Set oscillator frequency
+            0xA8, 0x3f, # Set multiplex ratio
+            0xD3, 0x00, # Set display offset
+            0x40,       # Set display start line
+            0x8D, 0x14, # Charge pump setting
+            0x20, 0x02, # Set Memory addressing mode
+            0xA1,       # Set Segment re-map
+            0xC8,       # Set COM output scan direction
+            0xDA, 0x12, # Set COM pins hardware configuration
+            0x81, 0xEF, # Set contrast control
+            0xD9, 0xA1, # Set pre-charge period
+            0xDB, 0x00, # Set VCOMH deselect level
+            0x2E,       # Deactivate scroll
+            0xA4,       # Output ram to display
+            0xA6,       # Normal display
+            0xAF,       # Display on
+        ]
+        self.send(init_cmds)
+        self.flush()