Period: Mid 80s
In times past, I used to build almost all of my own test equipment and technical tools. Most of them are long gone now, replaced by shiny commercial offerings. One item which remains however, and which I still use from time to time is this little EPROM programmer I built around 1986.
It is based on a 6809 processor, has 32k RAM for storing the EPROM image, and 4K for it's own purposes (It actually only needed a few bytes of local scratchpad storage, however I put on 4K so that I could download and test the firmware from RAM). A 6821 PIO chip handles the bidirectional data bus, and TTL latches drive the remaining control signals. It uses RELAYS to switch the programming voltage around as required, and the actual voltage used is set by a manual switch.
Firmware consists of a local keypad/7-segment interface, as well as a remote serial/RS-232 command interface. It supports standard and fast programming algorithms for a number of common EPROMS from the time period, and can upload and download common (Intel/Motorola) ASCII-HEX file formats.
Here is a look inside.
