altos/stm-vga: Implement VGA out from the STM processor

Generates vsync/hsync using timers and pixel data using the SPI port.
320x240 video using 640x480 mode and a 24MHz "pixel" clock.
Includes the beginings of rendering code for the frame buffer,
including bitblt, solid fill and text with a 5x7 font.

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

1 files changed, 33 insertions, 0 deletions

diff --git a/src/drivers/ao_vga.h b/src/drivers/ao_vga.h
new file mode 100644
index 00000000..caec8f48
--- /dev/null
+++ b/src/drivers/ao_vga.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright © 2016 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, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ */
+
+#ifndef _AO_VGA_H_
+#define _AO_VGA_H_
+
+#include "ao_draw.h"
+
+void
+ao_vga_init(void);
+
+void
+ao_vga_enable(int active);
+
+#define AO_VGA_WIDTH		320
+#define AO_VGA_HEIGHT		240
+#define AO_VGA_PAD		64
+#define AO_VGA_STRIDE		((AO_VGA_WIDTH + AO_VGA_PAD) >> AO_SHIFT)
+
+extern uint32_t	ao_vga_fb[AO_VGA_STRIDE * AO_VGA_HEIGHT];
+
+#endif /* _AO_VGA_H_ */