1 files changed, 74 insertions, 0 deletions
diff --git a/src/avr/ao_lcd_port.c b/src/avr/ao_lcd_port.c
new file mode 100644
index 00000000..b1e8aa17
--- /dev/null
+++ b/src/avr/ao_lcd_port.c
@@ -0,0 +1,74 @@
+/*
+ * Copyright © 2011 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include "ao.h"
+
+#define LCD_PORT	PORTB
+#define LCD_DDR		DDRB
+
+#define PIN_RS		4
+#define PIN_E		5
+#define PIN_RW		6
+
+static void
+ao_lcd_port_set_bits(uint8_t bits)
+{
+#if 0
+	printf("\tLCD data %x RS %d R/W %d E %d\n",
+	       bits & 0xf,
+	       (bits & (1 << PIN_RS)) ? 1 : 0,
+	       (bits & (1 << PIN_RW)) ? 1 : 0,
+	       (bits & (1 << PIN_E)) ? 1 : 0);
+#endif
+	LCD_PORT = bits;
+#if 0
+	ao_delay(1);
+	if (bits & (1 << PIN_RW))
+		printf("\tLCD input %x\n", PINB);
+#endif
+}
+
+uint8_t
+ao_lcd_port_get_nibble(uint8_t rs)
+{
+	uint8_t	data = (rs ? (1 << PIN_RS) : 0) | (1 << PIN_RW);
+	uint8_t n;
+
+	DDRB = (1 << PIN_RS) | (1 << PIN_E) | (1 << PIN_RW);
+	ao_lcd_port_set_bits(data);
+	ao_lcd_port_set_bits(data | (1 << PIN_E));
+	n = PINB & 0xf;
+	ao_lcd_port_set_bits(data);
+	return n;
+}
+
+void
+ao_lcd_port_put_nibble(uint8_t rs, uint8_t data)
+{
+	data = (data & 0xf) | (rs ? (1 << PIN_RS) : 0);
+	DDRB = (0xf) | (1 << PIN_RS) | (1 << PIN_E) | (1 << PIN_RW);
+	ao_lcd_port_set_bits(data);
+	ao_lcd_port_set_bits(data | (1 << PIN_E));
+	ao_lcd_port_set_bits(data);
+}
+
+void
+ao_lcd_port_init(void)
+{
+	DDRB = (1 << PIN_RS) | (1 << PIN_E) | (1 << PIN_RW);
+	PORTB = 0;
+}