VIDC20 Data Sheet
1.1.10 Horizontal Display End Register (HDER): Address 84H
fhis register defines the time, in pixels, from the start of the HSYNC pulse to the end of the video display. ;i.e. the first pixel which is not display).
ihis is a 14 bit register of which the bottom bit must be programmed to 0. If N pixels are required in this time, then value (N-18) should be programmed into the HBER (N must be a multiple of 2).
31 30 29 26 27 26 25 24 23 22 21 20 19 10 17 16 15 14 13 12 11 10 9 6 7 6 5 6 3 2 1 0
1 0 0 0 0 1 0 0	X % X X % X X X X X X X X-0]
HDER value
4.1.11 Horizontal Border End Register (HBER): Address SSH
This register defines the time, in pixels, from the start of the HSYNC puke to the end of the border display. (i.e. the fsst pixel which is not border).
This is a 14 bit register of which the bottom bit must be programmed to 0. If N pixels are required in this time, then value (N-12) should be programmed into the HBER (N must be a multiple of 2).
Again, if no border is required, this register must still be programmed such that N HgER = NIEDgR.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 6 7 6 5 4 3 2 1 0 1 0 0 0 0 1 0 7	x x x x z x x z x x x x X70
HBER value
4.1.12 Horizontal Cursor Start Register (HCSR): Address 86H
This register defines the time, in pixels, from the start of the HSYNC pulse to the start of the rower display.
This is a 14 bit register of which all bits may be programmed. If N pixels are required in this time, then value (N-17) should be programmed into the HCSR The cursor can thus be programmed to start on any pizeL In HiRes mode, the cursor can still only be programmed to start on a normal pixel boundary. However, because the resolution of the cursor can be defined to a micro-pixel, by using different cursor images it is possible to position the cursor to any micro-pixel.
Note that only the cursor start position needs to be defined, as the cursor is automatically disabled after 32 pixels in normal mode, or 16 pixels in HiRes mode. If a cursor smaller than this is required, then the remaining bits in the cursor pattern should be programmed to logical colour 00 (transparent).
31 30 29 28 27 26 25 26 23 22 21 20 19 16 17 16 15 14 13 12 11 10 9 6 7 6 5 4 3 2 1 0
1 0 0 0 0 1 1 0	X % X X XX X % X X X % % XI
HCfiR value
20