Add LCD device driver to STM32L port

This enables the 6-digit 14-character display on the STM32L discovery
board and provides an ascii output to it.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 101 insertions, 0 deletions

diff --git a/src/stm/ao_lcd_font.c b/src/stm/ao_lcd_font.c
new file mode 100644
index 00000000..f6074587
--- /dev/null
+++ b/src/stm/ao_lcd_font.c
@@ -0,0 +1,101 @@
+/*
+ * Copyright © 2012 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>
+
+static const uint16_t ao_lcd_font[] = {
+#include "ao_lcd_font.h"
+};
+
+/*
+	 ----- 		0
+	|\ | /|		1 2 3 4 5
+	| \|/ | @		14
+	 -- -- 		6 7
+	| /|\ |		8 9 10 11 12	
+	|/ | \| @		14
+	 ----- 		13
+	        @		15
+*/
+
+static const uint8_t	ao_bit_src[] = {
+	 8,  7,  5,  6,
+	13, 12,  0,  1,
+	10, 14,  4,  9,
+	11, 15,  3,  2
+};
+
+static const uint8_t	ao_bit_dst[6][4] = {
+	{  0,  1, 28, 29 },
+	{  2,  7, 26, 27 },
+	{  8,  9, 24, 25 },
+	{ 10, 11, 20, 21 },
+	{ 12, 13, 18, 19 },
+	{ 14, 15, 17, 16 },
+};
+
+static void
+ao_draw_glyph(uint8_t pos, uint16_t glyph) {
+	uint8_t		col, seg, src, dst;
+	uint32_t	ram;
+
+	for (col = 0; col < 4; col++) {
+		for (seg = 0; seg < 4; seg++) {
+			src = ao_bit_src[(col << 2) | seg];
+			dst = ao_bit_dst[pos][seg];
+			ram = stm_lcd.ram[col * 2];
+			ram &= ~(1 << dst);
+			ram |= (uint32_t) ((glyph >> src) & 1) << dst;
+			stm_lcd.ram[col*2] = ram;
+		}
+	}
+}
+
+#define AO_LCD_FONT_COLON	(1 << 14)
+#define AO_LCD_FONT_DECIMAL	(1 << 15)
+
+void
+ao_lcd_font_char(uint8_t pos, char c, uint16_t flags) {
+	if (pos > 5)
+		pos = 5;
+	if (c < ' ' || c > 127)
+		c = 127;
+	ao_draw_glyph(pos, ao_lcd_font[c - ' '] | flags);
+}
+
+void
+ao_lcd_font_string(char *s) {
+	uint8_t	pos = 0;
+	uint16_t flags;
+	char c;
+
+	while (pos < 6 && (c = *s++)) {
+		flags = 0;
+		for (;;) {
+			if (*s == ':')
+				flags |= AO_LCD_FONT_COLON;
+			else if (*s == '.')
+				flags |= AO_LCD_FONT_DECIMAL;
+			else
+				break;
+			s++;
+		}
+		ao_lcd_font_char(pos++, c, flags);
+	}
+	while (pos < 6)
+		ao_lcd_font_char(pos++, ' ', 0);
+}