; ===================================================
; Orion-128 computer
; System I/O ports
;
; Disassembled by Romychs @ 2026-10-08
; ===================================================


; System port mapped to RAM address.
; Matrix keyboard rows 0..7
PORT_F400_KBD  EQU 0xf400

; System port mapped to RAM address.
; Matrix keyboard columns 0..7
PORT_F401_KBD  EQU 0xf401

; System port mapped to RAM address.
;   bit 0 - Tape Output
;   bit 2 - Output "RUS/LAT" LED indicator
;   bit 3 - Output "TapeIn" LED indicator
;   bit 4 - Tape Input
;   bit 5 - Input "Ctrl" keyboard key
;   bit 6 - Input "Shift" keyboard key
;   bit 7 - Input "RUS/LAT" keyboard key
PORT_F402_KBD  EQU 0xf402

; System port mapped to RAM address.
PORT_F500_USR1 EQU 0xf500

; System port mapped to RAM address.
; Used to output LPT Data
PORT_F600_USR2 EQU 0xf600

; System port mapped to RAM address.
PORT_F601_USR2 EQU 0xf601

; System port mapped to RAM address.
; LPT Control port:
;   bit 3 - input BUSY sygnal
;   bit 7 - output #STROBE sygnal
PORT_F602_USR2 EQU 0xf602

; System port mapped to RAM address.
PORT_F603_USR2 EQU 0xf603

; System port mapped to RAM address.
; VG93 State/Command
FDC_F700_STATE EQU 0xf700

; System port mapped to RAM address.
; VG93 Track number
FDC_F701_TRACK EQU 0xf701

; System port mapped to RAM address.
; VG93 Sector number
FDC_F702_SECTOR EQU 0xf702

; System port mapped to RAM address.
; VG93 read/write data from floppy
FDC_F703_DATA  EQU 0xf703

; System port mapped to RAM address.
FDC_F704_REQ   EQU 0xf704

; System port mapped to RAM address.
; Select floppy disk side
FDC_F708_SIDE  EQU 0xf708


; --------------------------------------------------
; Write only system port mapped to RAM address.
; Set video mode.
;    bit 0 - palette 0-1, 1-2;
;    bit 1 - color count 0 - 16 colors, 1 - 4 colors;
;    bit 2 - 0-mono, 1-color;
; --------------------------------------------------
PORT_SYS1   EQU 0xF8


; Write only system port mapped to RAM address.
; Set active RAM page
; bits D[3:0] - page number
PORT_SYS2   EQU 0xf900

; Write only system port mapped to RAM address.
; Switch Screen
; bits D[1:0] - screen number;
; bit  D6 - RAM Refresh;
; bit  D7 - 12k/16k (384px/512px screen width)
PORT_SYS3   EQU 0xfa00

; Write only system port mapped to RAM address.
PORT_SYS4   EQU 0xfb00

; ===================================================
; I/O Ports
; ===================================================

; Set active RAM page
; bits D[3:0] - page number
P_SW_MEM    EQU 0xf9

; Switch screen RAM window
; D1 D0
;  0  0 — screen 1 (0xС000—0xEFFF)
;  0  1 — screen 2 (0x8000—0xAFFF)
;  1  0 — screen 3 (0x4000—0x6FFF)
;  1  1 — screen 4 (0x0000—0x2FFF)
P_SW_SCR   EQU 0xfa