Loading from cartridge on the ZX Spectrum

After we acquired and restored our Sinclair ZX Spectrum, we wanted a quick way to load games and using a tape was not an option. Due to the bad experiences, we had trying to convert TAP files to WAV and then recording them on tape, we decided to look for an alternative. The only way to quickly load files was to use some kind of cartridge-based add-on that plugs in directly to the Spectrum. After a short google search, we found the ZX Dandanator Mini. This piece of hardware is an external memory peripheral that is built like a cartridge. Its general purpose is to be a platform for developing and releasing game cartridges and also serves perfectly as a loader for Z80, TAP, SNA and ROM files. The great thing about the Dandanator is that it supports loading multiple files in the EEPROM and it comes with a software package that allows you to create custom menus. We decided to give it a try and we ordered a bunch of boards from our favorite PCB manufacturer using the Gerber files we found on the web. After the package arrived, we began to assemble our Dandanator cartridge.

The parts needed are:

  • 10k resistors – 2x
  • 100nf capacitors – 5x
  • 1N4148 diode
  • microswitches – 2x
  • PIC16F1826
  • 18-pin socket for the PIC microcontroller
  • 39SF040 EEPROM
  • PLC32 socket for the EEPROM
  • GAL22V10
  • 24-pin socket for the GAL chip
  • DB-9 female connector for the kempston joystick port
  • 60-pin card edge connector (this needs to be modified by removing 1 pin out of the beginning and ending of each row and after that removing the fifth pin from the top and bottom row, so that it matches the PCB footprint.)

The GAL and EEPROM were all programed with the TL866 programer using the provided JED file and ROM created with the rom genereator software. The PIC microcontroler was programed with the pickit3 programer using the provided hex file. All files can be found on the official page of the ZX Dandanator project.

All components layed on the bench

Starting from the shortest components – the two 10k resistors and 1N4148 diode

Installing the two sockets for the PIC and EEPROM and two female headers for the GAL chip. We use somddddde tape to hold the in place when soldering.

Adding the five 100nf capacitors

Adding the 9-pin kempston port and the two microswitches

Adding the modified card edge connector

ROM Generator – Main screen

Selecting files to load in ROMGenrating the ROM file by clicking the “Create ROM” button

Finally installing all the chips

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