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Name: N 80 Z
Type: 80 column card (videx compatible)
Short description:
For Apple ][+ only. Goes usually into slot 3. Switching to
graphics (or 40 column text) is done via softswitch.
Installation:
The N 80 Z fits into any slot (except 0 and 7). Slot 3 is
recommended for Pascal and CP/M.
It has a 14 pin IC-socket, which needs to be plugged between
IC F 14 (74LS259) on the main board and its socket:
Remove IC F 14, located left near the color trim poti, plug
N 80 Z socket into the motherboard socket and then put
IC F 14 back on the top into the N 80 Z socket.
The male BNC connector goes into the Apple's video out connector
and the female BNC connector goes to the monitor.
Jumper settings:
No jumpers. Phew...
Usage:
Simply type PR#3. The screen should switch automatically to
80 column display.
Key sequences:
Ctrl-Z 0 Clear screen
Ctrl-Z 1 Return to 40 column mode
Ctrl-Z 3 Alternate charset
Ctrl-Z followed by
Ctrl-@ to G Lores graphic characters
Ctrl-Z followed by
Ctrl-P to Ctrl-Shift-O Line graphic characters
Ctrl-Z followed by
Ctrl-H to Ctrl-O Abbrev. for control character
Ctrl-A Toggle caps lock
Ctrl-G Bell
Ctrl-H Backspace
Ctrl-J Line feed
Ctrl-K Clear to end of page
Ctrl-L Clear screen
Ctrl-M Carriage return
Ctrl-S Stop/Start
Ctrl-U Cursor forward
Ctrl-Y Home (without clear)
ESC followed by
A to F Like on the Apple screen
Ctrl-Shft-M Clear to end of line
Ctrl-Shft-N followed by
two characters X and Y Set cursor to X Y; the characters
are calculated as X+31 and Y+31
Register settings of CRT-controller:
register r/w normal value Name
00: w 7B Horiz. total
01: w 50 Horiz. displayed
02: w 62 Horiz. sync pos
03: w 29 Horiz. sync width
04: w 1B Vert. total
05: w 08 Vert. adjust
06: w 18 Vert. displayed
07: w 19 Vert. sync pos
08: w 00 Interlaced
09: w 08 Max. scan line
10: w C0 Cursor upper
11: w 08 Cursor lower
12: w 00 Startpos Hi
13: w 00 Startpos Lo
14: r/w 00 Cursor Hi
15: r/w 00 Cursor Lo
16: r 00 Lightpen Hi
17: r 00 Lightpen Lo
Register is read (Slot 3 assumed):
LDA #{body}lt;register>
STA $C0B0
LDA $C0B1
Register is written:
LDA #{body}lt;register>
STA $C0B0
LDA #{body}lt;value>
STA $C0B1
The card has 2kB rom, 4kB character rom and 2kB video ram.
The rom is mapped into $CN00-$CNXFF (N is slotno) and $C800-$CBFF,
the video ram is mapped (in four banks) at $CC00-$CDFF.
Bank switching is done via accessing the addresses (slot 3 assumed)
$C0B0, $C0B4, $C0B8 and $C0BC.
Memory locations used:
$06F8: Screen start address (divided by 16)
$07F8: Status:
Bit 0: normal/alternate charset
Bit 4: 18 or 24 lines
Bit 6: caps lock flag
Bit 7: GET/GETLN flag
$C058: Switch off card
$C059: Switch on card