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(MESS) Add documentation (nw)

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R. Belmont 2014-01-02 22:09:28 +00:00
parent 65e4aa12a2
commit c0f502adfb
1 changed files with 19 additions and 1 deletions
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src/mess/drivers/pt68k4.c
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@ -15,7 +15,25 @@ Some pics: http://www.wormfood.net/old_computers/
Note: bios 0 works with the terminal. When first started, press Enter
to get the logo. Enter HE to get a list of commands. Terminate
numeric entries with a Space (not Enter!).
Chips:
68230 Parallel Interface/Timer @ FE0080
68681 DUART/Timer (x2) @ FE0000 and FE0040
WD37C65 FDC @ FE0101/3/etc (compatible with PC NEC765)
Floppy drive select @ FE00C1: bits 0/1 drive select 0-3, bit 5 = 1 for double density, bit 6 = side select
MK48T02 TimeKeeper @ FF0FF1/3/5/etc.
Keyboard at FE01C1 (status/IRQ clear)/FE01C3 (AT scan codes)
Video: ISA MDA or CGA-style boards
MDA maps VRAM at D60000, 6845 address at FA0769, 6845 data at FA076B, control latch at FA0771
CGA maps VRAM at D70000, 6845 address at FA07A9, 6845 data at FA07AB, control port at FA07B1, color set at FA07B3, CGA status at FA07B5
HUMBUG BIOS tests MDA and CGA VRAM to determine existence, falls back to serial console if neither exists. If both exist, MDA is used.
VRAM is every other byte for ISA cards. (Only 8 bit cards are supported).
IRQs:
5: keyboard has new scan code available, all others don't exist
****************************************************************************/
#include "emu.h"