* Code cleanup.

* Made the configure() function of PinDriver interface optional to allow manual pin configuration.
RoboCraft · Feb 3, 2012 · 755e041 · 755e041
1 parent c1b6abf
commit 755e041
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Showing 2 changed files with 24 additions and 21 deletions.
diff --git a/hd44780.c b/hd44780.c
@@ -29,7 +29,6 @@ HD44780_Result hd44780_init(HD44780 *display, HD44780_Mode mode,
 {
   HD44780_RETURN_ASSERT(display != NULL, HD44780_ERROR);
   HD44780_RETURN_ASSERT(hal != NULL, HD44780_ERROR);
-  HD44780_RETURN_ASSERT(hal->pins.configure != NULL, HD44780_ERROR);
   HD44780_RETURN_ASSERT(hal->pins.write != NULL, HD44780_ERROR);
   HD44780_RETURN_ASSERT(hal->delay_microseconds != NULL, HD44780_ERROR);
   HD44780_RETURN_ASSERT(pinout != NULL, HD44780_ERROR);
@@ -39,17 +38,20 @@ HD44780_Result hd44780_init(HD44780 *display, HD44780_Mode mode,
   display->hal = *hal;
   display->pinout = *pinout;
 
-  display->hal.pins.configure(&display->pinout.rs, HD44780_PIN_OUTPUT);
-  display->hal.pins.configure(&display->pinout.en, HD44780_PIN_OUTPUT);
+  if (display->hal.pins.configure != NULL)
+  {
+    display->hal.pins.configure(&display->pinout.rs, HD44780_PIN_OUTPUT);
+    display->hal.pins.configure(&display->pinout.en, HD44780_PIN_OUTPUT);
 
-  if (display->pinout.rw.gpio != NULL)
-    display->hal.pins.configure(&display->pinout.rw, HD44780_PIN_OUTPUT);
+    if (display->pinout.rw.gpio != NULL)
+      display->hal.pins.configure(&display->pinout.rw, HD44780_PIN_OUTPUT);
+
+    if (display->pinout.backlight.gpio != NULL)
+      display->hal.pins.configure(&display->pinout.backlight, HD44780_PIN_OUTPUT);
+  }
 
   if (display->pinout.backlight.gpio != NULL)
-  {
-    display->hal.pins.configure(&display->pinout.backlight, HD44780_PIN_OUTPUT);
     display->hal.pins.write(&display->pinout.backlight, HD44780_PIN_LOW);
-  }
 
   if (mode == HD44780_MODE_4BIT)
   {
@@ -273,7 +275,7 @@ HD44780_Result hd44780_right_to_left(HD44780 *display)
   return hd44780_command(display, HD44780_CMD_ENTRYMODESET | display->displaymode);
 }
 
-/* FIXME moves the cursor off screen */
+/* FIXME moves the cursor out of screen */
 HD44780_Result hd44780_create_char(HD44780 *display, uint8_t location, const uint8_t *charmap)
 {
   HD44780_RETURN_ASSERT(display != NULL, HD44780_ERROR);
@@ -309,12 +311,13 @@ HD44780_Result hd44780_config(HD44780 *display)
 {
   HD44780_RETURN_ASSERT(display != NULL, HD44780_ERROR);
   HD44780_RETURN_ASSERT(display->hal.delay_microseconds != NULL, HD44780_ERROR);
-  HD44780_RETURN_ASSERT(display->hal.pins.configure != NULL, HD44780_ERROR);
   HD44780_RETURN_ASSERT(display->hal.pins.write != NULL, HD44780_ERROR);
 
   for (unsigned i = 0; i < display->dp_amount; ++i)
   {
-    display->hal.pins.configure(&display->pinout.dp[display->dp_offset + i], HD44780_PIN_OUTPUT);
+    if (display->hal.pins.configure != NULL)
+      display->hal.pins.configure(&display->pinout.dp[display->dp_offset + i], HD44780_PIN_OUTPUT);
+
     display->hal.pins.write(&display->pinout.dp[display->dp_offset + i], HD44780_PIN_LOW);
   }
 

diff --git a/hd44780.h b/hd44780.h
@@ -60,17 +60,20 @@ typedef struct
 typedef struct
 {
   HD44780_Pin rs;         // LOW: command.  HIGH: character.
-  HD44780_Pin en;     // activated by a HIGH pulse.
-  HD44780_Pin rw;         // LOW: write to LCD.  HIGH: read from LCD.
-  HD44780_Pin backlight;  // should be connected to base/gate of transistor/FET
-  HD44780_Pin dp[8];      // data pins
+  HD44780_Pin en;         // activated by a HIGH pulse.
+  HD44780_Pin rw;         // optional; LOW: write to LCD.  HIGH: read from LCD.
+  HD44780_Pin backlight;  // optional; should be connected to base/gate of transistor/FET
+  HD44780_Pin dp[8];      // data pins DP0..DP7; DP0..DP3 are optional if using 4-bit mode
 } HD44780_Pinout;
 
 typedef enum { HD44780_OK, HD44780_ERROR } HD44780_Result;
 typedef enum { HD44780_PIN_INPUT, HD44780_PIN_OUTPUT } HD44780_PinMode;
 typedef enum { HD44780_PIN_LOW, HD44780_PIN_HIGH } HD44780_PinState;
 
-/* Hardware-dependent pin control interface */
+/* Hardware-dependent pin control interface.
+ * configure() function is optional if you want to configure
+ * the display pins manually.
+ */
 typedef struct
 {
   HD44780_Result (*configure)(HD44780_Pin *pin, HD44780_PinMode mode);
@@ -142,15 +145,12 @@ HD44780_Result hd44780_write8bits(HD44780 *display, uint8_t value);
 HD44780_Result hd44780_write4bits(HD44780 *display, uint8_t value);
 HD44780_Result hd44780_pulse_enable_pin(HD44780 *display);
 
-#define HD44780_MAKE_8BITS(b0,b1,b2,b3,b4,b5,b6,b7) \
+#define HD44780_MAKE_5BITS(b4,b3,b2,b1,b0) \
     (((b0) & 1) | \
      ((b1) & 1) << 1 | \
      ((b2) & 1) << 2 | \
      ((b3) & 1) << 3 | \
-     ((b4) & 1) << 4 | \
-     ((b5) & 1) << 5 | \
-     ((b6) & 1) << 6 | \
-     ((b7) & 1) << 7)
+     ((b4) & 1) << 4)
 
 #ifdef __cplusplus
 }