Tiny Eprommer

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Tiny Eprommer
Type: EPROM programmer
Producer: DIY, kit from Conrad Electronic
Price: about 30 DM (DIY)
Released: 1988
Info: released in 64'er Magazine 8/88

Tiny-EPROMer (also: Tiny Eprommer) is a C64 hardware device that creates (or ‘burns’) EPROMs (Erasable Programmable Read-Only Memory). It first appeared as an electronics project in 64'er Magazine 8/88 and was re-released in special issue 84 in 1992.

Purpose[edit | edit source]

Modded Kernal

EPROMs allow replacing the C64's ROMs by custom versions using an adapter PCB. Alternate KERNALs range from slightly modded stock variants (e.g., with modified start-up screen text and colors) to larger modifications such as JiffyDOS. Using a device such as a Switchless Kernal or Dual Kernal adapter, the user can choose between multiple KERNALs.

EPROMs are also used in building expansion port cartridges.

Features[edit | edit source]

  • Very simple hardware: Only one IC, single-sided PCBs
  • Connects to the C64 user / joystick ports
  • Supports EPROMs 2764 (8 KBytes) to 27256 (32 KBytes), with additional adapter or in revised variant (see Links) 27512 (64 KBytes), too
  • Supports 12,5 volts and 21 volts programming voltage

Usage[edit | edit source]

PRG files need to contain a loading address (i.e., files have to be of size 8194/16386/32770 bytes). The address is ignored on load.

The eprom should only get inserted into the socket once the software has been started already as the hardware may apply 21 volts voltage on C64 startup or with other running software.

The programming voltage has to match the individual eprom's requirements. If a too high voltage is selected, the eprom will get destroyed. Programming an eprom with a voltage too low will fail. Best practice is to search for the eprom's datasheet on the web (search for the exact part number plus the manufacturer's name) and look up its programming voltage Vpp.

Programming 27512 eproms is done in two 32KBytes passes and flipping some switches between passes.

Programming software

Links[edit | edit source]