1 files changed, 69 insertions, 0 deletions
diff --git a/lcd.c b/lcd.c
new file mode 100644
index 0000000..927b90f
--- /dev/null
+++ b/lcd.c
@@ -0,0 +1,69 @@
+#include "lcd.h"
+
+#include <avr/io.h>
+#include <util/delay.h>
+
+#define B_SRCLK		PB0
+#define B_LCDE		PB3
+#define B_SRD_LCDRS	PB4
+
+static void lcd_pin(bool value)
+{
+	/* cheat, put the clock in front.
+	 * result:
+	 * clk, d0 | clk, d1 | clk... d7 | clk, rs.
+	 *  ^- first clk ignored            ^- last clk from setting R/S
+	 */
+	PORTB |= (1 << B_SRCLK);
+	PORTB &= ~(1 << B_SRCLK);
+
+	if (value)
+		PORTB |= (1 << B_SRD_LCDRS);
+	else
+		PORTB &= ~(1 << B_SRD_LCDRS);
+}
+
+void lcd_command(uint8_t cmd, bool isdata)
+{
+	uint8_t i;
+
+	for (i = 1;      i; i <<= 2)
+		lcd_pin(cmd & i);
+	for (i = 1 << 7; i; i >>= 2)
+		lcd_pin(cmd & i);
+
+	lcd_pin(isdata);
+	__asm__ ("nop\n");
+	PORTB |= (1 << B_LCDE);
+	__asm__ ("nop\n");
+	PORTB &= ~(1 << B_LCDE);
+	__asm__ ("nop\n");
+	if (!isdata)
+		_delay_us(50);
+}
+
+void lcd_puts(const char * PROGMEM ptr, uint8_t cnt)
+{
+	while (cnt--) {
+		uint8_t ch = __LPM(ptr++);
+		lcd_put(ch);
+	}
+}
+
+const char PROGMEM boot[] = "boot";
+
+void lcd_init(void)
+{
+	PORTB &= ~((1 << B_SRCLK) | (1 << B_LCDE) | (1 << B_SRD_LCDRS));
+	DDRB |= (1 << B_SRCLK) | (1 << B_LCDE) | (1 << B_SRD_LCDRS);
+	_delay_ms(15);
+
+	lcd_command(0x38, 0);
+	lcd_command(0x0c, 0);
+	lcd_command(0x06, 0);
+	lcd_command(0x02, 0);
+	_delay_ms(2);
+
+	lcd_line1();
+	lcd_puts(boot, sizeof(boot) - 1);
+}