altos: Split out arch-specific bits of LCD driver

[fw/altos] / src / avr / ao_lcd_port.c

diff --git a/src/avr/ao_lcd_port.c b/src/avr/ao_lcd_port.c
new file mode 100644 (file)
index 0000000..b1e8aa1
--- /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;
+}