Introduction

EPROM Programmers come in different sizes and are designed to program individual chips with

• different footprints that either
  • plug in directly
  • or use additional adapters

before connecting to the ZIF zero-insertion sockets supplied with the programmer.In some cases the physical chip or the footprint is not always available.

In the case of some older 8-bit game computers and the Z88 card for example, the flash or EPROM chip is inside a plug-able module. The address and data lines are available via a bespoke connector. The EPROM programmer could also program a chip with more memory than the programmer is normally able to program if the most significant bit individual address signal lines are changed by hardware. Larger size devices could then be programmed in multiple steps. Finally the user may know which signals need to be swapped, changed or held at a different logic level and would welcome a board to try different combinations before the solution is found, either be theory or by trail and error.

The object of this card is to design a PCB that can be used in a variety of ways depending which components are fitted allowing the user to have full hardware control of the signals used.

Types of EPROM Programmers

The following types of EPROM Programmers have been identified.

• 32 pin
• 40 pin
• 48 pin

The 40 and 48 pin programmers are able to program larger memory devices as they have more address lines available. Allowing the user to manually set the most significant bit individual address signal lines using tri-state switches, allow these larger devices to be programmed by a 32 pin programmer.

The lever that grips the chip can either be at the top left-hand side or the bottom right-hand side of the ZIF socket. The card needs to be designed so that it does not fowl the lever.

Design

The design of the card is split in 3 parts where the first and last parts are similar and the middle part translates the desired signals.

Source - Plug to fit into the ZIF socket of the EPROM programmer

• Address Tri-state switches
• Header for additional address lines
• Space for 2 off 24 pin headers to be used for 48 pin programmers. Shorter lengths may be fitted for the smaller sizes of programmers.
• These headers are repeated if jumper wires are used to connect directly to the output.
• Tracks are marked with a section that allows them to be permanently cut.
• Another row of headers may be fitted the other side of these cuts, so that the tracks may be reconnected using header links.

Translation Section

• 2 x 12 way DIP switches
• Tri-state switches (?)

Target - 48 pin ZIF Socket - Additional connector

• This allows up to the a maximum size 48 pin zif socket to be used.
• The headers are repeated so that jumper wires may be used.
• Tracks are marked with a section that allows them to be permanently be cut.
• Tracks may be reconnected using a header link
• 48 pin IDC connector to allow connection to non standard external cards
• Z88 card socket connector

Parts List

 

CONNECTOR, HEADER, THT, 2.54MM, 50WAY	2	109-6994
CABLE ASSY, RIBBON 34WAY		101-2214
SOCKET, IC, ZIF, 32WAY		113-6782
PCB, EUROCARD, FR4, 2.54MM	0.25	117-2137
HEADER, STRAIGHT, 16WAY	4+2	124-8124
SOCKET, VERTICAL, 16WAY	4	341-9174
HEADER, RIGHT ANGLE, 0.1", 8WAY	1	588-775
HOUSING, 26AWG, 8WAY (A19)	2	109-8717
RIBBON CABLE, IDT, 8WAY (A19)	1	131-3461
SWITCH, 4POLE, 3 POS, PCB	1	112-3698
KNOB, 15.7MM, BLACK, YELLOW LINE	1	144-1137
WIRE, PTFE, A, GREEN, 1/0.4MM, 25M	1/25	118-4004

 

Circuit Diagram

The circuit diagram of this card can be viewed by clicking here (which will open in a new window).