1.1 --- a/examples/vga/vga.h Sat Nov 03 16:42:17 2018 +0100
1.2 +++ b/examples/vga/vga.h Sat Nov 03 21:47:40 2018 +0100
1.3 @@ -23,8 +23,8 @@
1.4 #include "vga_common.h"
1.5
1.6 #define LINE_LENGTH 160 /* pixels */
1.7 -#define LINE_COUNT 256 /* distinct display lines */
1.8 -#define LINE_MULTIPLIER (SCANLINES / LINE_COUNT)
1.9 +#define LINE_COUNT 256 /* display lines per frame */
1.10 +#define FRAME_COUNT 1 /* double-buffered display */
1.11
1.12 /* 24MHz cycle measurements. */
1.13
1.14 @@ -37,6 +37,12 @@
1.15
1.16 #define SCREEN_SIZE (LINE_LENGTH * LINE_COUNT)
1.17
1.18 +/* A frame has an entire screen plus one line to allow horizontal scrolling,
1.19 + since a horizontal scroll offset causes the final transfer line to exceed the
1.20 + screen limit. */
1.21 +
1.22 +#define FRAME_SIZE (SCREEN_SIZE + LINE_COUNT)
1.23 +
1.24 /* Transfer and pixel allocation properties. */
1.25
1.26 #define TRANSFER_CELL_SIZE LINE_LENGTH