Microchip PIC Clock

It was February of 1998 when I first put my eye on the Microchip PIC microcontroller product line. It all started many years earlier with a Commodore C-64, followed by homebrew 6502 hardware projects and a fair bit of assembler programming on the 6502. Maybe some day I will find those notes if they still exist. After the 6502 adventures came a 8051 based project. In those days flash memory or EEPROM were unheard of. The project called for a single chip embedded processor. Philips made it, but only with masked ROM. For development, an 8051 with piggyback EPROM was available. Yes, the cermaic body of the 8051 actually had gold pins for an EPROM on its back! Unfortunately that chip was prohibitively expensive (for a student budget) and the project never materialized beyond hardware concept and some initial coding.

Today I raided my filing cabinet for some PIC related info and discovered my earliest PIC projects. This was the first of them. The code was well preserved on a floppy disk. Finding some machine with a floppy drive was whole different story, worth telling another day…

The design was based on a PIC18F84 processor. The pictures show the circuit assembled on a protoboard. The PIC16F84 had insufficient I/O lines for driving four 7-segment LED displays. The displays were multiplexed to reduce the I/O line requirements. Sorry, the schematic lacks component information if you really must know part numbers I can look them up…

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