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Diffstat (limited to 'src/mame/video/beezer.c')
-rw-r--r--src/mame/video/beezer.c70
1 files changed, 70 insertions, 0 deletions
diff --git a/src/mame/video/beezer.c b/src/mame/video/beezer.c
new file mode 100644
index 00000000000..2b05958c830
--- /dev/null
+++ b/src/mame/video/beezer.c
@@ -0,0 +1,70 @@
+#include "driver.h"
+#include "cpu/m6809/m6809.h"
+#include "machine/6522via.h"
+
+static int scanline=0;
+
+INTERRUPT_GEN( beezer_interrupt )
+{
+ scanline = (scanline + 1) % 0x80;
+ via_0_ca2_w (0, scanline & 0x10);
+ if ((scanline & 0x78) == 0x78)
+ cpunum_set_input_line(0, M6809_FIRQ_LINE, ASSERT_LINE);
+ else
+ cpunum_set_input_line(0, M6809_FIRQ_LINE, CLEAR_LINE);
+}
+
+VIDEO_UPDATE( beezer )
+{
+ int x,y;
+
+ for (y = machine->screen[0].visarea.min_y; y <= machine->screen[0].visarea.max_y; y+=2)
+ {
+ for (x = machine->screen[0].visarea.min_x; x <= machine->screen[0].visarea.max_x; x++)
+ {
+ *BITMAP_ADDR16(bitmap, y+1, x) = machine->pens[videoram[0x80*y+x] & 0x0f];
+ *BITMAP_ADDR16(bitmap, y, x) = machine->pens[(videoram[0x80*y+x] >> 4)& 0x0f];
+ }
+ }
+
+ return 0;
+}
+
+WRITE8_HANDLER( beezer_map_w )
+{
+ /*
+ bit 7 -- 330 ohm resistor -- BLUE
+ -- 560 ohm resistor -- BLUE
+ -- 330 ohm resistor -- GREEN
+ -- 560 ohm resistor -- GREEN
+ -- 1.2 kohm resistor -- GREEN
+ -- 330 ohm resistor -- RED
+ -- 560 ohm resistor -- RED
+ bit 0 -- 1.2 kohm resistor -- RED
+ */
+
+ int r, g, b, bit0, bit1, bit2;
+
+ /* red component */
+ bit0 = (data >> 0) & 0x01;
+ bit1 = (data >> 1) & 0x01;
+ bit2 = (data >> 2) & 0x01;
+ r = 0x26 * bit0 + 0x50 * bit1 + 0x89 * bit2;
+ /* green component */
+ bit0 = (data >> 3) & 0x01;
+ bit1 = (data >> 4) & 0x01;
+ bit2 = (data >> 5) & 0x01;
+ g = 0x26 * bit0 + 0x50 * bit1 + 0x89 * bit2;
+ /* blue component */
+ bit0 = (data >> 6) & 0x01;
+ bit1 = (data >> 7) & 0x01;
+ b = 0x5f * bit0 + 0xa0 * bit1;
+
+ palette_set_color(Machine, offset, MAKE_RGB(r, g, b));
+}
+
+READ8_HANDLER( beezer_line_r )
+{
+ return (scanline & 0xfe) << 1;
+}
+