Broken likely due to timing

Signed-off-by: Collin J. Doering <collin.doering@rekahsoft.ca>

lcdLib.c

@@ -51,16 +51,13 @@ void clkLCD(void) {
 void loop_until_LCD_BF_clear(void) {
   LCD_CTRL_PORT = (LCD_CTRL_PORT & ~(1 << LCD_RS)) | (1 << LCD_RW); // RS=0, RW=1
   LCD_DBUS_DDR &= ~(1 << LCD_BF); // Set LCD_BF as input
-  clkLCD();
 
   STATUS_LED_PORT |= 1 << STATUS_LED; // DEBUG
-  while (bit_is_clear(LCD_DBUS_PIN, LCD_BF)) {
+  do {
     clkLCD();
-  }
-
+  } while (bit_is_clear(LCD_DBUS_PIN, LCD_BF));
   /* loop_until_bit_is_clear(LCD_DBUS_PIN, LCD_BF); */
   STATUS_LED_PORT &= ~(1 << STATUS_LED); // DEBUG
-
     
   LCD_DBUS_DDR = 0xff; // Reset all LCD_DBUS_PORT pins as outputs
 }
@@ -97,9 +94,14 @@ void writeStringToLCD(const char* str) {
   }
 }
 
-void clearScreen(void) {
-  writeLCDInstr(CMD_CLEAR_SCREEN);
-  _delay_us(LCD_CLEAR_SCREEN_DELAY);
+void clearDisplay(void) {
+  writeLCDInstr(CMD_CLEAR_DISPLAY);
+  _delay_us(LCD_CLEAR_DISPLAY_DELAY);
+}
+
+void returnHome(void) {
+  writeLCDInstr(CMD_RETURN_HOME);
+  _delay_us(LCD_RETURN_HOME_DELAY);
 }
 
 char readCharFromLCD(void) {
@@ -135,7 +137,7 @@ static inline void disableLCDOutput(void) {
 static inline void softwareLCDInitPulse(void) {
   enableLCDOutput();
   LCD_CTRL_PORT &= ~((1 << LCD_RS) | (1 << LCD_RW)); // RS=RW=0
-  LCD_DBUS_PORT = 0x30;
+  LCD_DBUS_PORT = CMD_INIT;
   clkLCD();
 }
 
@@ -143,36 +145,40 @@ static inline void softwareLCDInitPulse(void) {
   Do software initialization as specified by the datasheet
 */
 void initLCD (void) {
-  _delay_ms(30);     // Wait 15ms as per datasheet
+  enableLCDOutput();
+
+  // Wait minimum 15ms as per datasheet
+  _delay_ms(LCD_INIT_DELAY0);
 
   softwareLCDInitPulse();
   
-  // Disable transmission and wait minimum 4.1ms as per datasheet
-  //disableLCDOutput();
-  _delay_us(8200);
+  // Wait minimum 4.1ms as per datasheet
+  _delay_us(LCD_INIT_DELAY1);
 
   softwareLCDInitPulse();
 
-  // Disable transmission and wait minimum 100us as per datasheet
-  //disableLCDOutput();
-  _delay_us(200);
+  // Wait minimum 100us as per datasheet
+  _delay_us(LCD_INIT_DELAY2);
 
   softwareLCDInitPulse();
 
   // Function set (2 lines with 5x7 dot character font)
-  writeLCDInstr_(0x38); // RS=RW=0, 0b00111000
+  writeLCDInstr_(0x38); // RS=RW=0, 0b00111000, 0x38
 
-  /* BF now has to be checked */
+  /* BF now can be checked */
 
   // Set functions of LCD
-  writeLCDInstr_(0x08); // Display off
-  _delay_ms(1);
-  writeLCDInstr_(0x01); // Clear display
-  _delay_ms(16);
-  //_delay_us(15200 - LCD_DELAY); // Extra delay for clear display
+  writeLCDInstr_(INSTR_DISPLAY); // Display off
+  _delay_us(LCD_GENERIC_INSTR_DELAY);
+
+  writeLCDInstr_(CMD_CLEAR_DISPLAY); // Clear display
+  _delay_us(LCD_CLEAR_DISPLAY_DELAY);
+
   writeLCDInstr_(0x06); // Increment mode, no shift
-  _delay_ms(1);
+  _delay_us(LCD_GENERIC_INSTR_DELAY);
+
   writeLCDInstr_(0x0E); // Display on, cursor on, blink off
+  _delay_us(LCD_GENERIC_INSTR_DELAY);
 
   flashLED(5); // DEBUG
 }

lcdLib.h

@@ -46,14 +46,54 @@
 #define LCD_DBUS7     PB7
 #define LCD_BF        PB7
 
-// LCD delays (in microseconds)
-#define LCD_DELAY              50
-#define LCD_CLEAR_SCREEN_DELAY 16000
-#define LCD_SEND_DELAY         40 // unused
+// LCD in 4 bit mode (default is 8 bit mode)
+//#define FOUR_BIT_MODE
+
+// LCD delays (in microseconds when unspecified)
+#define LCD_DELAY               1
+#define LCD_INIT_DELAY0         30    // milliseconds
+#define LCD_INIT_DELAY1         8200
+#define LCD_INIT_DELAY2         200
+
+#define LCD_CLEAR_DISPLAY_DELAY 16000
+#define LCD_RETURN_HOME_DELAY   16000
+#define LCD_GENERIC_INSTR_DELAY 50
+
+/* LCD Commands */
+
+// Simple commands with no options
+#define CMD_INIT             0x30
+#define CMD_CLEAR_DISPLAY    0x01
+#define CMD_RETURN_HOME      0x02
+
+// Entry Set instruction and associated options
+#define INSTR_ENTRY_SET      0x04
+#define INSTR_ENTRY_SET_ID   0x02
+#define INSTR_ENTRY_SET_S    0x01
+
+// Display control instruction and associated options
+#define INSTR_DISPLAY        0x08
+#define INSTR_DISPLAY_D      0x04
+#define INSTR_DISPLAY_C      0x02
+#define INSTR_DISPLAY_B      0x01
+
+// Cursor or display shift instruction and associated options
+#define INSTR_MOV_SHIFT      0x10
+#define INSTR_MOV_SHIFT_SC   0x08
+#define INSTR_MOV_SHIFT_RL   0x04
+
+// Function set instruction and associated options
+#define INSTR_FUNC_SET       0x20
+#define INSTR_FUNC_SET_DL    4
+#define INSTR_FUNC_SET_N     3
+#define INSTR_FUNC_SET_F     2
+
+// Set CG RAM address instruction
+#define INSTR_CGRAM_ADDR     0x60
+
+// Set DD RAM address instruction
+#define INSTR_DDRAM_ADDR     0x80
 
-// LCD Commands
-#define CMD_CLEAR_SCREEN 0x01
-#define CMD_RETURN_HOME  0x02
 
 //------------------------------------
 
@@ -80,7 +120,9 @@ void writeCharToLCD(char c);
 
 void writeStringToLCD(const char* str);
 
-void clearScreen(void);
+void clearDisplay(void);
+
+void returnHome(void);
 
 char readCharFromLCD(void);
 

lcdOutput.c

@@ -50,7 +50,7 @@ int main(void) {
       writeStringToLCD(data[i]);
     }
     _delay_ms(5000);
-    clearScreen();
+    clearDisplay();
 
 
     //flashLED(5); // DEBUG