Jupiter-II
Another Jupiter Ace computer clone
Main differences from the original Jupiter Ace
- Buffered composite video output
- Reset button
- Inversed video jumper selection
- Two screen pages and two character sets area (selectable at the video expansion connector)
- Reduced chip count with PLDs replacing several TTL logic
- Additional signals in expansion connectors
For more information on the original Jupiter Ace computer and an extensive software collection visit The Jupiter Ace Archive
The Jupiter-II Expansion
See the Jupiter-II Expansion project for adding:
- Video Colour
- Programmable Sound Generator
- 128K paged RAM
- Serial Interface
- FORTH vocabulary extension (Color, Memory Paging, Sound Generator, etc.)
Jumper Settings
Inverse Video Jumper
- Jumper installed: Black text on white background (inversed)
- Jumper removed: White text on black background (default)
ROM image selection Jumper
- Jumper installed: Original Jupiter Ace 8K ROM image
- Jumper removed: Boot with the Jupiter-II Expansion
The original Jupiter Ace 8K ROM image can be found at The Jupiter Ace Archive.
Connections
Power Supply
Connect a 7.5Vdc to 9 Vdc x 1A power supply. Center pin is positive.
A/V output
- pin 1: Audio Output (BEEP)
- pin 2: Common
- pin 3: Composite Video Output
The video standard is 60Hz NTSC compatible but converting to 50Hz PAL by recoding the PLDs shall not be too difficult.
Tape I/O
- pin 1: MIC output (for LOADing)
- pin 2: Common
- pin 3: EAR input (for SAVEing)
Expansion
50 pin header connector (2x25 female). Similar layout as the original Jupiter Ace with additional pins "-ROMSL" and "SPEAKER"
- pin 1:GND , pin 2:GND
- pin 3:-INT , pin 4:GND
- pin 5:-NMI , pin 6:+9Vdc
- pin 7:-HALT , pin 8:+5Vdc
- pin 9:-MREQ , pin 10:-CLK
- pin 11:-IORQ , pin 12:A11
- pin 13:-RD , pin 14:A12
- pin 15:-WR , pin 16:A13
- pin 17:-BUSACK , pin 18:A14
- pin 19:-WAIT , pin 20:A15
- pin 21:-BUSRQ , pin 22:D4
- pin 23:-RESET , pin 24:D3
- pin 25:-M1 , pin 26:D5
- pin 27:-RFSH , pin 28:A2
- pin 29:A6 , pin 30:A10
- pin 31:A5 , pin 32:A9
- pin 33:A4 , pin 34:A8
- pin 35:A3 , pin 36:A7
- pin 37:A1 , pin 38:A0
- pin 39:D0 , pin 40:D1
- pin 41:D2 , pin 42:D6
- pin 43:D7 , pin 44:-WE
- pin 45:(n.c.) , pin 46:(n.c.)
- pin 47:-ROMSL , pin 48:SPEAKER
- pin 49:(n.c.) , pin 50:(n.c.)
(n.c.) means not connected
-ROMSL (in) Disables internal ROM chip when connected to +5V
SPEAKER (out) TTL level Speaker signal (BEEP)
Video Expansion
30 pins header connector (2x15 female). Similar layout as the original Jupiter Ace with some additional pins.
- pin 1:VA3 , pin 2:VA0
- pin 3:VA5 , pin 4:VA4
- pin 5:VD2 , pin 6:VD3
- pin 7:VD1 , pin 8:VD4
- pin 9:VA6 , pin 10:VD0
- pin 11:VA2 , pin 12:VD7
- pin 13:-VRAMWR , pin 14:VD5
- pin 15:VA8 , pin 16:VA7
- pin 17:VA9 , pin 18:VA1
- pin 19:VD6 , pin 20:-VLOAD
- pin 21:+5Vdc , pin 22:GND
- pin 23:-CPAGE , pin 24:-SPAGE
- pin 25:-SCRRAM , pin 26:-VSYNC
- pin 27:BORDER , pin 28:-HSYNC
- pin 29:LUMA , pin 30:BLANK
-VRAMWR (out) Video RAM write enable
-CPAGE (in) Character Generator page selection
-SPAGE (in) Screen page selection
-SCRRAM (out) Screen RAM enabled
-VSYNC (out) Vertical Video Synch
-HSYNC (out) Horizontal Video Synch
LUMA (out) Video Luminance
BLANK (out) Video Blanking (retrace blanking)