Les projets de VE2CUY

Mini i86 Dos machine

Document converti depuis ve2cuy.com/blog — publié le 2011-01-31 — dernière modification : 2011-01-31

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I am currently working on a mini i86 DOS machine.

An old modified PC-XT board serve as a test platform for the homemade BIOS.

All IO’s – keyboard, VGA Display, floppy disk, RS232 will be handle by a propeller chip board.

To date,

INT10 (video) and
INT 16 (keyboard) are working.

I am currently working on INT13 (disk) function.

An image disk of DOS 3.1 will be on a SD flash drive connected to the propeller chip.

To date, with INT13 AH=02 (read); sector 0, side 0, track 0, I am able to load DOS boot sector from the propeller chip.

Some pictures:

Video at:

▶️ Vidéo YouTube : Voir la vidéo

Extract of propeller keyboard micro-code:

PRI sendKey(request)

dataToSend

dataToSend := 0 ‘ DATA to return to the 8088

if request == KEYB_AVAILABLE
if kb.gotkey
dataToSend := kb.keyNoRetrieve

if request == KEYB_GET_KEY
dataToSend := kb.getkey

outa[15..8] := dataToSend

outa[DATA_AVAILABLE_FOR_8088] := 1
waitcnt(Delay_on + cnt) ‘ Wait a moment so the 8088 has time to read it

outa[8..15] := 0
outa[DATA_AVAILABLE_FOR_8088] := 0
waitcnt(Delay_off + cnt)

return 0

Extract of Mini DOS Machine BIOS:

; Project: MINI DOS MACHINE BIOS
; Auteur: Alain Boudreault (VE2CUY)
; Date: 2010.01.10
;——————————————————————————–

.code
ORG 0h

start: jmp cold
include data.inc
COLD: MOV AX,40h
MOV DS,AX
MOV Word ptr DS:72h,0

WARM:

include cpu_test.asm

JZ CPU_OK
HALT: HLT

CPU_OK:

include init_8xxxChips.asm
include Get_MemSize.asm
include Install_int_vectors.asm
ifdef INST_BASIC_ROM
include Inst_Basic_Rom.asm
endif

include Check_Devices.asm

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