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The Trumpcard

  Designed by Innovonics to overcome the Aces edge connector lay out. By wiring the trumpcard to the ZX81 layout will allow you to use ZX81 peripherals with the Ace.

Side A

Side B

Trumpcard 22 pin Edge connector

Trumpcard wired up by Brian Bates.


   Trumpcard was originally designed as a mechanical and electrical link between the Jupiter Ace and ZX peripherals. To maintain flexibility and programmability the two connecting edges are quite separate. In this way the constructor can colour code and interrupt the signal lines as he pleases, both for experimental and permanent applications.
   With the exception of the chip select lines, WE on the ACE and RAM/ROM CS. on the ZX 81, both computers share the same bus albeit in a different configuration.

   Trumpcard topside - Side A has the ZX polarizing slot at top left. Side B is underside.

Connector Preparation
1. Bend connector pins outwards at their midpoint approx. 30°
2. Bend pins back to centre at their base, such that pinends leave just enough room to accept the Trumpcard PCB.
3. Ensuring pin ends are flat against PCB tracks, insert card and align right ' most pins ( adjacent to connector polarising key ) with Track 2 Side A.

   0.6 mm single core connecting wire is recommended. Multi core wire is prone to causing shorts after soldering but can be used if necessary. If thin telephone wire is used, all lines can be routed through holes, otherwise construct as per instructions below.

1. Slide connector pins approx. 3 mm over PCB tracks on the un slotted edge of the card leaving sufficient room to solder connecting wires. Check that the top row of pins is well clear of the bottom row, particularly at their bending point.
2. Taking care that the card lies parallel to connector body, tack solder the outermost pins on both sides to the PCB. This facilitates the soldering of the remaining pins, which should be held flush to the PCB tracks for a neater finish. 3. Prepare interconnection wires by paring off 3 mm insulation at both ends.
4. Following the interconnection tables, assemble the underside first, starting at ACE 2B and working thru to 22B. 15B to 19B will need to be threaded under some of the control lines, in order to work through the tracks consecutively.
Leave at least 4mm of track free on the ZX side to allow the peripheral to seat properly when applied.
5. Turn the assembly over, soldering from ACE 23A to 3A consecutively. Only 10T passes through a hole. Thread the remaining wires between connector body and PCB over its edge to side B.

N.B. Check your connections and inspect work for solder splashes.
TTL chips carry a maximum 7V0 rating !!

Having checked your wiring thoroughly, attach your peripheral to the card, then holding the card attach it to the ACE's Expansion port. Ensure both peripheral and ACE are on a stable flat surface. N.B. The ACE PCB polarising slot is slightly wider than the connector key itself. With the keyboard facing you and Trumpcard attached, push the connector firmly to the right of the slot - you may hear it click home. Check this point, as a perfectly wired card may not function if connector pins and ACE PCB tracks are slightly misaligned. Screen white-outs or a scrolling cursor indicate a poor or wrong connection.

I/O boards, D/A's, A/D's etc will require homegrown software to test them.
RAMpacks of 16, 32, and 64K will return unsigned RAMTOPS of 32768, 49152 and 65536 ( screen display -32768, -16384, 0 respectively ) by typing 15384 @ . which is the ACE's RAMTOP system variable. If the machine crashes, switch off, make necessary adjustments and switch on again. Unless the 9V line is wrongly connected, it is very unlikely that either the ACE or your peripheral is damaged. Check your assembly closely and all should be well.

ALTERNATIVE APPLICATIONS Trumpcard need not be used only on the ACE, similarly, the ZX tracks can be used to attach other types of connectors. E.G. Ribbon cable 0.05 and 0.1 pitch/ PCB header pins straight or right-angled on 0.1 centres/ wire wrap DIL sockets 0.3" and 0.6". Even 'D' Type subminiature Sockets/Plugs with solder bucket connectors will slip snugly over the PCB edge. The buckets themselves will have to be wired separately - they are not on the same pitch as the PCB tracks.

WIRING TABLE      A = Topside B = Underside

ACE Wire Length ZX Route Signal ACE Wire Length ZX Route Signal
3A 2¼" 7A D6 1B
4A 2¼" 5A D1 2B 2" 11A INT
5A 2¼" 17B Edge A0 3B 2" 12A NMI
6A 2¼"  5B Edge A7 4B 2" 13A H3 HALT
7A 2¼" 6B Edge A8 5B 2" 14A H3 MREQ
8A 2¼" 7B Edge A9 6B 2" 15A H3 IORQ
9A 2¼" 8B Edge A10 7B 2" 16A H3 RD
10A 2" 15B H2 A2 8B 2" 17A H3 WR
11A 1½" 8A D5 9B 2" 18A H3 BUSAK
12A 1½" 9A D3 10B 2" 19A H3 WAIT
13A 1¼" 10A D4 11B 2" 20A H3 BUSRQ
14A 2¼" 13B Edge A15 12B 2" 21A H3 RESET
15A 2¼" 12B Edge A14 13B 2" 22A H3 M1
16A 2¼" 11B Edge A13 14B 2" 23A H3 RFSH
17A 2ΒΌ" 10B Edge A12 15B 1¾" 4B A6
18A 2¼" 9B Edge A11 16B 1¾" 3B A5
19A 2¼" 18B Edge 0CIK 17B 1¾" 2B A4
20A 2¼" 23B Edge 5V 18B 2" 14B A3
21A 2¼" 22B Edge 9V 19B 2" 16B A1
22A 20B 4A H1 D0
23A 19B+20B Edge 0V 21B 6A D2
        22B 1A D7
Hole 1 is at left when card in viewed from top.
Trumpcard numbering system is independent of any ZX81 convention.
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