validate SPI comm interface with ssd1306_128x64_spi

app/modules/u8g.c

@@ -1046,6 +1046,51 @@ static int lu8g_ssd1306_128x64_i2c( lua_State *L )
     return 1;
 }
 
+// Lua: object = u8g.ssd1306_128x64_spi( cs, dc )
+static int lu8g_ssd1306_128x64_spi( lua_State *L )
+{
+    unsigned cs = luaL_checkinteger( L, 1 );
+    if (cs == 0)
+        return luaL_error( L, "CS pin required" );
+    unsigned dc = luaL_checkinteger( L, 2 );
+    if (dc == 0)
+        return luaL_error( L, "D/C pin required" );
+
+    lu8g_userdata_t *lud = (lu8g_userdata_t *) lua_newuserdata( L, sizeof( lu8g_userdata_t ) );
+
+    // We don't use the pre-defined device structure for u8g_dev_ssd1306_128x64_i2c here
+    // Reason: linking the pre-defined structures allocates RAM for the device/comm structure
+    //         *before* the display is constructed (especially the page buffers)
+    //         this consumes heap even when the device is not used at all
+#if 1
+    // build device entry
+    lud->dev = (u8g_dev_t){ u8g_dev_ssd1306_128x64_fn, &(lud->pb), U8G_COM_HW_SPI };
+
+    // populate and allocate page buffer
+    // constants taken from u8g_dev_ssd1306_128x64.c:
+    //                     PAGE_HEIGHT
+    //                      | Height
+    //                      |  |              WIDTH
+    //                      |  |               |
+    lud->pb = (u8g_pb_t){ { 8, 64, 0, 0, 0 }, 128, NULL };
+    //
+    if ((lud->pb.buf = (void *)c_zalloc(lud->pb.width)) == NULL)
+        return luaL_error( L, "out of memory" );
+
+    // and finally init device using specific interface init function
+    u8g_InitHWSPI( LU8G, &(lud->dev), cs, dc, U8G_PIN_NONE );
+#else
+    u8g_InitHWSPI( LU8G, &u8g_dev_ssd1306_128x64_spi, cs, dc, U8G_PIN_NONE );
+#endif
+
+
+    // set its metatable
+    luaL_getmetatable(L, "u8g.display");
+    lua_setmetatable(L, -2);
+
+    return 1;
+}
+
 
 // Module function map
 #define MIN_OPT_LEVEL 2
@@ -1111,6 +1156,7 @@ static const LUA_REG_TYPE lu8g_display_map[] =
 const LUA_REG_TYPE lu8g_map[] = 
 {
     { LSTRKEY( "ssd1306_128x64_i2c" ), LFUNCVAL ( lu8g_ssd1306_128x64_i2c ) },
+    { LSTRKEY( "ssd1306_128x64_spi" ), LFUNCVAL ( lu8g_ssd1306_128x64_spi ) },
 #if LUA_OPTIMIZE_MEMORY > 0
 
     // Register fonts

lua_examples/u8g_bitmaps.lua

@@ -1,13 +1,28 @@
 
 -- setup I2c and connect display
 function init_i2c_display()
-     sda = 5
+     -- SDA and SCL can be assigned freely to available GPIOs
-     scl = 6
+     sda = 5 -- GPIO14
+     scl = 6 -- GPIO12
      sla = 0x3c
      i2c.setup(0, sda, scl, i2c.SLOW)
      disp = u8g.ssd1306_128x64_i2c(sla)
 end
 
+-- setup SPI and connect display
+function init_spi_display()
+     -- Hardware SPI CLK  = GPIO14
+     -- Hardware SPI MOSI = GPIO13
+     -- Hardware SPI MISO = GPIO12 (not used)
+     -- CS and D/C can be assigned freely to available GPIOs
+     cs = 8 -- GPIO15, pull-down 10k to GND
+     dc = 4 -- GPIO2
+
+     spi.setup(1, spi.MASTER, spi.CPOL_LOW, spi.CPHA_LOW, spi.DATABITS_8, 0)
+     disp = u8g.ssd1306_128x64_spi(cs, dc)
+end
+
+
 function xbm_picture()
      disp:setFont(u8g.font_6x10)
      disp:drawStr( 0, 10, "XBM picture")
@@ -34,9 +49,7 @@ function draw(draw_state)
 end
 
 
-function bitmap_test()
+function bitmap_test(delay)
-     init_i2c_display()
-
      -- read XBM picture
      file.open("u8glib_logo.xbm", "r")
      xbm_data = file.read()
@@ -58,10 +71,13 @@ function bitmap_test()
                draw(draw_state)
           until disp:nextPage() == false
 
+          tmr.delay(delay)
           tmr.wdclr()
      end
 
      print("--- Bitmap Test done ---")
 end
 
-bitmap_test()
+--init_i2c_display()
+init_spi_display()
+bitmap_test(50000)

lua_examples/u8g_graphics_test.lua

@@ -1,13 +1,27 @@
 
 -- setup I2c and connect display
 function init_i2c_display()
-     sda = 5
+     -- SDA and SCL can be assigned freely to available GPIOs
-     scl = 6
+     sda = 5 -- GPIO14
+     scl = 6 -- GPIO12
      sla = 0x3c
      i2c.setup(0, sda, scl, i2c.SLOW)
      disp = u8g.ssd1306_128x64_i2c(sla)
 end
 
+-- setup SPI and connect display
+function init_spi_display()
+     -- Hardware SPI CLK  = GPIO14
+     -- Hardware SPI MOSI = GPIO13
+     -- Hardware SPI MISO = GPIO12 (not used)
+     -- CS and D/C can be assigned freely to available GPIOs
+     cs = 8 -- GPIO15, pull-down 10k to GND
+     dc = 4 -- GPIO2
+
+     spi.setup(1, spi.MASTER, spi.CPOL_LOW, spi.CPHA_LOW, spi.DATABITS_8, 0)
+     disp = u8g.ssd1306_128x64_spi(cs, dc)
+end
+
 
 -- graphic test components
 function prepare()
@@ -122,9 +136,7 @@ function draw(draw_state)
      end
 end
 
-function graphics_test()
+function graphics_test(delay)
-     init_i2c_display()
-
      print("--- Starting Graphics Test ---")
 
      -- cycle through all components
@@ -135,6 +147,7 @@ function graphics_test()
                draw(draw_state)
           until disp:nextPage() == false
           --print(node.heap())
+          tmr.delay(delay)
           -- re-trigger Watchdog!
           tmr.wdclr()
      end
@@ -142,4 +155,6 @@ function graphics_test()
      print("--- Graphics Test done ---")
 end
 
-graphics_test()
+--init_i2c_display()
+init_spi_display()
+graphics_test(50000)

lua_examples/u8g_rotation.lua

@@ -1,13 +1,28 @@
 
 -- setup I2c and connect display
 function init_i2c_display()
-     sda = 5
+     -- SDA and SCL can be assigned freely to available GPIOs
-     scl = 6
+     sda = 5 -- GPIO14
+     scl = 6 -- GPIO12
      sla = 0x3c
      i2c.setup(0, sda, scl, i2c.SLOW)
      disp = u8g.ssd1306_128x64_i2c(sla)
 end
 
+-- setup SPI and connect display
+function init_spi_display()
+     -- Hardware SPI CLK  = GPIO14
+     -- Hardware SPI MOSI = GPIO13
+     -- Hardware SPI MISO = GPIO12 (not used)
+     -- CS and D/C can be assigned freely to available GPIOs
+     cs = 8 -- GPIO15, pull-down 10k to GND
+     dc = 4 -- GPIO2
+
+     spi.setup(1, spi.MASTER, spi.CPOL_LOW, spi.CPHA_LOW, spi.DATABITS_8, 0)
+     disp = u8g.ssd1306_128x64_spi(cs, dc)
+end
+
+
 -- the draw() routine
 function draw()
      disp:setFont(u8g.font_6x10)
@@ -35,13 +50,12 @@ function rotate()
 
           dir = dir + 1
           dir = bit.band(dir, 3)
+          -- schedule next rotation step in 1000ms
           next_rotation = tmr.now() / 1000 + 1000
      end
 end
 
 function rotation_test()
-     init_i2c_display()
-
      print("--- Starting Rotation Test ---")
      dir = 0
      next_rotation = 0
@@ -55,10 +69,13 @@ function rotation_test()
                draw(draw_state)
           until disp:nextPage() == false
 
+          tmr.delay(100000)
           tmr.wdclr()
      end
 
      print("--- Rotation Test done ---")
 end
 
+--init_i2c_display()
+init_spi_display()
 rotation_test()