bryaq / pacific80-rom

Pacific-80 ROM

BUILD

You'll need

• A85 assembler
• ZMAC assembler
• monobit font converter
• make, srecored, iconv from your distribution's package repository

INSTALL

Burn either 27c512.hex, 27c256.hex, 27c128.hex or 27c64.hex to your EPROM chip.

USE

CP/M disk format

CBIOS expects CF card to be formatted with MBR using LBR addressing and up to 4 primary partions of type 52h and size up to 8MB each. First 'track' of a partiotion is sytem track, put CCP+BDOS there, so CP/M can boot. You can access filesystem on these partitions or partition images from PC using either

• cpmtools
• cpmfuse
• cpmcbfs

cpmtools-compatible disk definition:

diskdef pac80
  seclen 512
  tracks 1024
  sectrk 16
  blocksize 8192
  maxdir 512
  skew 0
  boottrk 1
  os 2.2
end

MEMORY MAP

256K memory space is divided to 16 16KB-pages. 64KB CPU address space is divided to 4 16KB-banks. Each bank can be mapped to any page. After reset all banks are mapped to page f. Video memory starts at 1810h offset in each video page/plane. Column 0 at 1810h-18ffh, column 1 at 1910h-19ffh, and so on, total 40 columns. Plane 0 color is navy blue, plane 1 color is sand, both planes together give white.

Page	Type	Notes
0	RAM
1	RAM
2	RAM
3	RAM
4	RAM	video page 0 plane 0 at 1810-3fff
5	RAM	video page 0 plane 1 at 1810-3fff
6	RAM	video page 1 plane 0 at 1810-3fff
7	RAM	video page 1 plane 1 at 1810-3fff
8	RAM	optional
9	RAM	optional
a	RAM	optional
b	RAM	optional
c	RAM	optional
d	RAM	optional
e	RAM	optional
f	ROM

I/O PORTS

Port	Assigned to
00-07	EXT0
10-17	EXT1
20-27	EXT2
30-37	CF
08	BANK0
48	BANK1
88	BANK2
c8	BANK3
1a	PPI PORT A
1b	PPI PORT B (SEL=1)
19	PPI PORT B (SEL=0)
1c	PPI PORT C
1d	PPI CONTROL
28	UART DATA
29	UART CONTROL/STATUS
38	PSG

8255 ports

	Function	SEL=0	SEL=1	2nd 0	2nd 1	3rd 0	3rd 1	4th 0	4th 1
PB0	gamepad	UP	UP	UP	UP	0	Z	1	UP
PB1	gamepad	DOWN	DOWN	DOWN	DOWN	0	Y	1	DOWN
PB2	gamepad	0	LEFT	0	LEFT	0	X	1	LEFT
PB3	gamepad	0	RIGHT	0	RIGHT	0	MODE	1	RIGHT
PB4	gamepad	A	B	A	B	A	B	A	B
PB5	gamepad	START	C	START	C	START	C	START	C
PB6	gamepad	0	1	0	1	0	1	0	1
PB7	always=1	1	1	1	1	1	1	1	1

	WRITE	READ
PC0	video page	video page
PC1	VBLANK interrupt enable	VBLANK interrupt enable
PC2	UART interrupt enable	UART interrupt enable
PC3		keyboard interrupt request
PC4	keyboard interrupt enable	keyboard strobe
PC5		keyboard input buffer full
PC6		VBLANK interrupt request
PC7		UART interrupt request