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The Way Back page

Some of the things I did way back in my late teens and early twenties.

Starting in 1980 with my first computer, the 6502 based UK101 all the way through to the Record Time digital clock in 1986.

All this was done before the Internet, my primary source of information came from magazines like Elektor, Wireless World, Practical Electronics and Electronics Today International as well as the Sybex books on the 6502 and the bible of logic, Texas Instruments TTL databook in two volumes.

My first computer, 6502 based Compukit UK101

EEPROM programmer for 2516/2716.  The daughter board was a Vpp mod' to get both 25 volts and 13 volts for different EEPROM types if I recall correctly.

My first homebrew computer, built on stripboard with a 6502 CPU, 2K RAM.  I had to rob it of all the chips to build my next one.

Homebrew terminal.  Used a 6502 CPU with 6845 video controller. I wrote the entire assembler code myself and hand designed the character set.  It supported multiple text windows.

 This keyboard was a project in Elektor magazine from the early 1980's and cost me 44GBP for the kit.  It has a Hex keypad on the right.

My second homebrew computer. The P51.  Again based on a 6502 with a 6847 video controller, General InstrumentsI AY3-8910 sound generator, serial port with programmable bit rate generator,

The last of my homebrew computers.  Using a eurobus backplane card from Elektor magazine and my own custom bus. 

 

From front to back

  • 6502 CPU card + parallel printer port

  • I/O card, parallel and serial I/F

  • EEPROM emulator card

  • 64K (8x8K) paged memory card

Reverse side of one of the cards. Wired by hand using Verowire solder through wiring system.  Many hours of work went into these boards

Another view of the CPU card

Left to right

  • I/O card, parallel and serial I/F

  • 6502 CPU card + parallel printer port

  • 64K (8x8K) paged memory card

  • EEPROM emulator card

A single board 6502 based controller

Digital clock. Bi colour LEDs around the outside show hours, 7 segment display in the centre shows minutes.

Inside of the Digital clock.  Built around a 6502 CPU, featured alarm, chime, display dimmer.

 this square intentionally left blank

Record Time

Built in 1986, still working in 2013

Built using an Intel 8748 EEPROM microcontroller.  Using AC mains 50/60Hz for time keeping with auto-detect of the main frequency.

 

Another view of the control board for the Record Time clock