Build rough functions for 4bit parrallel use.

1602LCD_char_display.c

@@ -15,73 +15,197 @@
 #define RS_DDR  DDD0
 
 
-#define RW_PORT PORTD
-#define RW_PIN  PIND1
-#define RW_DDR  DDD1
+//#define RW_PORT PORTD
+//#define RW_PIN  PIND1
+//#define RW_DDR  DDD1
 
 
 #define ENA_PORT PORTD
-#define ENA_PIN  PIND2
-#define ENA_DDR  DDD2
+#define ENA_PIN  PIND1
+#define ENA_DDR  DDD1
 
 #define BIT4_PORT   PORTD
-#define BIT4_PIN    PIND3
-#define BIT4_DDR    DDD3
+#define BIT4_PIN    PIND4
+#define BIT4_DDR    DDD4
 
 
 #define BIT5_PORT   PORTD
-#define BIT5_PIN    PIND4
-#define BIT5_DDR    DDD4
+#define BIT5_PIN    PIND5
+#define BIT5_DDR    DDD5
 
 #define BIT6_PORT   PORTD
-#define BIT6_PIN    PIND5
-#define BIT6_DDR    DDD5
+#define BIT6_PIN    PIND6
+#define BIT6_DDR    DDD6
 
 #define BIT7_PORT   PORTD
-#define BIT7_PIN    PIND6
-#define BIT7_DDR    DDD6
+#define BIT7_PIN    PIND7
+#define BIT7_DDR    DDD7
 
 #define LED_PIN     PINC0
 #define LED_PORT    PORTC
 #define LED_DDR     DDC0
 
-//LCD CONNECTIONS
-//PIND0 RS, H: data input L: Instruction input
-//PIND1 RW, H: read L: write
-//PIND2 ENABLE, Enable signal
-//PIND3 BIT4
-//PIND4 BIT5
-//PIND5 BIT6
-//PIND6 BIT7
+//LCD CONNECTIONS:
+/*
+ * VSS --> GND
+ * VDD --> VCC
+ * V0  --> POT --> GND
+ * RS  --> PD0(AVR)
+ * RW  --> GND
+ * E   --> PD1(AVR)
+ * D4  --> PD4(AVR)
+ * D5  --> PD5(AVR)
+ * D6  --> PD6(AVR)
+ * D7  --> PD7(AVR)
+ *
+ * PURPOSE:
+ * RS: register select,
+ * RW: Read/Write select signal,
+ * E:  Operation(data read/write) enable signal.
+ * DB0~DB3: not used for 4bit operations.
+ * DB4~DB7: high order three-state data lines.
+ */
+
+//#############################
+//MACROS
+//#############################
+
+//already defined
+//#define _BV(bit) (1 << bit)
+#define setbit(port, bit) (port) |= (1 << (bit))
+#define clearbit(port, bit) (port) &= ~(1 << (bit))
+
+
+
+//#############################
+//FUNCTION PROTOTYPES
+//#############################
+
+
+void init_lcd(void);
+//void cmd_lcd(uint8_t cmd);
+void cmd_nibble_lcd(uint8_t cmd);
+void clear_lcd(void);                                                                                               
+static void led_blink(void);
+void set_lcd_one_line_(void);
+void set_lcd_two_line(void);
+void return_home_lcd(void);
+void turn_off_lcd(void);
+void turn_on_lcd(void);
+void set_cgram_lcd_address(uint8_t addr);
+void set_ddram_lcd_address(uint8_t addr);
+void write_lcd_address(uint8_t addr);
+
+
+
+int main() {
+    //SETUP HERE.
+    _delay_ms(500);
+    while(1) {
+        led_blink();
+        _delay_ms(1000);
+        set_lcd_one_line();
+        _delay_ms(1000);
+        set_lcd_two_line();
+    }
+    
+    return 0;
+}
+
+
 
 //#############################
 //FUNCTIONS
 //#############################
 
 void init_lcd(void) {
-    DDRD |= (1<<RS_DDR)|(1<<RW_DDR)|(1<<ENA_DDR)|
-        (1<<BIT4_PIN)|(1<<BIT5_PIN)|(1<<BIT6_PIN)|(1<<BIT7_PIN);
-
-    _delay_ms(40);
-
-    PORTD = (0<<RS_PIN)|(0<<RW_PIN)|(0<<ENA_PIN)|
-        (1<<BIT4_PIN)|(1<<BIT5_PIN)|(0<<BIT6_PIN)|(1<<BIT7_PIN);
-
-    _delay_ms_(5);
-
-    PORTD = (0<<RS_PIN)|(0<<RW_PIN)|(0<<ENA_PIN)|
-        (1<<BIT4_PIN)|(1<<BIT5_PIN)|(0<<BIT6_PIN)|(1<<BIT7_PIN);
-
-    _delay_ms(1);
+    //allow us to read pin7
+    DDRD = 0x00;
+    setbit(DDRD, BIT7_DDR);
+    while(PORTD & (1<<BIT7_PIN)){
+        led_blink(); 
+    }
 
+    DDRD = 0xff; //All output
+    _delay_ms(20);
+    
+    set_lcd_two_line();
+    return_home_lcd();
+    clear_lcd();
 
 }
 
-void cmd_lcd() {
+
+/*
+ * Input: None
+ * Outupt: None
+ * Description: Sets the LCD into 4bit two line display mode.
+ */
+void set_lcd_two_line(void) {
+    cmd_nibble_lcd(0x20);
+    cmd_nibble_lcd(0x80);
+}
+
+void set_lcd_one_line(void) {
+    cmd_nibble_lcd(0x20);
+    cmd_nibble_lcd(0x00);   
+}
+
+void clear_lcd(void) {
+    cmd_nibble_lcd(0x00);
+    cmd_nibble_lcd(0x10);
+}
+
+void return_home_lcd(void) {
+    cmd_nibble_lcd(0x00);
+    cmd_nibble_lcd(0x20);
+}
+
+void turn_off_lcd(void) {
+    cmd_nibble_lcd(0x00);
+    cmd_nibble_lcd(0x80);
+}
+
+
+void turn_on_lcd(void) {
+    cmd_nibble_lcd(0x00);
+    cmd_nibble_lcd(0x80);
+}
+
+
+void set_cgram_lcd_address(uint8_t addr) {
 ;
 }
 
 
+void set_ddram_lcd_address(uint8_t addr) {
+;
+}
+
+
+void write_lcd_address(uint8_t addr) {
+;
+}
+
+
+//A version that doesn't require multiple calls.
+void cmd_lcd(uint8_t cmd) {
+;
+}
+
+void cmd_nibble_lcd(uint8_t cmd) {
+    DDRD = 0xff;
+    PORTD &= 0x0f;
+
+    setbit(PORTD, ENA_PIN);
+    PORTD |= cmd;
+    _delay_ms(1);
+    clearbit(PORTD, ENA_PIN);
+    _delay_ms(1);
+}
+
+
+
 /*
  * Input: None
  * Output: None
@@ -98,16 +222,4 @@ static void led_blink(void) {
     
 }
 
-int main() {
-    //SETUP HERE.
-    init_lcd(); 
 
-    while(1) {
-        led_blink();
-        test_lcd();
-        _delay_ms(1000);
-        off_lcd();
-    }
-    
-    return 0;
-}