ZX bus splitter
Board dedicated to 100×50×17 case (internal dimensions). Can be used with ZX Spectrum, Timex Computer 2068, Timex Sinclair 2068 and ZX81/TS1500. Unused contacts must be cuted out.
Can be used in several configurations:
- Two vertical boards with parallel tracks can be soldered - this gives three-ways bus splitter. Distance between vertical boards is 31.75mm (1.25").
- Universal board can can be connected as parallel -- simple, through interface can be made (extra memory, AY, joystick, printer, DMA controller, faster Z80, slots like: cartridge, ISA, YABUS). Distance between signal rows connectors -- 35.6mm (1.4").
- Can be cuted into 2 separate small boards -- this gives two double bus splitters or interface can be mounted vertically in a 100×17 case.
Version v004 contains in addition:
- Place for 74LS139 SMD chip, that can be used to swith output signals (like /IORQ and /MREQ) to one of 3 edge connectors or to none of them.
- Place for DIP-SWITCH to select active edge connector.
- Place for 74LS153 SMD chip that can be used to switch input signals (like /INT, /NMI) from one of 3 edge connectors or from none of them.
- Two places for microswitches, that can be connected to /RESET and /NMI. One is on the left, second on the right.
- Place for DB9 connector. (A Kempston Joystick port can be mounted using reconfigured places for SMD chips - 74LS138 and 74LS368 should be used in that case.)
- Places for LEDs.
Files for download
- 0012b.jpg 76.9kB (2007-08-13 14:53)
- ZX.SPLIT for ZX81 - extra 74HCT139 decodes A5=1 and A7=1 for ZX1541 due to port conflict with joystick (port 29). Bottom view.
- 0012t.jpg 69.7kB (2007-08-13 14:51)
- ZX.SPLIT for ZX81 - extra 74HCT139 decodes A5=1 and A7=1 for ZX1541 due to port conflict with joystick (port 29). Top view.
- 0006tc.jpg 80.4kB (2007-04-25 18:25)
- ZX.SPLIT used as three-ways bus splitter. Top case view.
- 0006bu.jpg 107.7kB (2007-04-25 18:25)
- ZX.SPLIT used as three-ways bus splitter. Bottom uncased view. Only one slot gets /MREQ can generate /ROMCS=1.
- 0006bc.jpg 93.3kB (2007-04-25 18:25)
- ZX.SPLIT used as three-ways bus splitter. Bottom case view.
- 0006tu.jpg 113.7kB (2007-04-25 18:26)
- ZX.SPLIT used as three-ways bus splitter. Top uncased view. The DIP-Switch selects active slot.
- 0002a.jpg 144.3kB (2007-04-28 00:51), uploaded by Jarek Adamski
- ZX.SPLIT as bottom board for ZX81 interface. Please note how the board is corrected with 16 jumpers.
- spli-005.zip 53.5kB (2006-10-31 18:39)
- Board v005, Eagle data files. This project has bugs, but 32 boards are producted. Needs some changes when used as bottom of universal interface.
- spli-004.zip 57.5kB (2006-10-31 18:39)
- Board v004, Eagle data files. This project is correct.
- howtocut.jpg 140.2kB (2006-10-31 18:30)
- How the ZX.SPLIT can be cuted for ZX81, ZX Spectrum and Timex 2068. Also halves used as Timex Twister and ZX+3 fixer. (Board v005.)
- split003.png 8.9kB (2005-04-12 21:24)
- Recent project board view.
Links to other pages
- [pl] Request for comments on forum.
- ISA slots for ZX Spectrum (I/O mapped). LPT, 2×RS232, Floppy Disk Controller and sound card.
- ZX1541 : ZX81
- Commodore 1541 disk interface for ZX81.