The purpose of this tiny little program is to reset drum counter of Laserjet III – compatibles laser printers (like the Olivetti PG308, that I owned).
Those printers have a little cartridge on which the drum counter is written. When the counter reach 10000, the printer stop working until a new drum unit (and a new cartridge) is loaded.
This is obviously a Bad Thing, and the fact that my drum unit printed more than 72000 sheets before I scraped the printer clearly prove this! :)
Just connect the cartridge to the PC parallel port with a special cable (also built by me), click on the Program button and counter is reset to 0 copies.
Clearly on my new printer (samsung CLX-3175… the worst printer I ever had!) there was a much sophisticated system to prevent use of compatible or refilled cartridges. But nothing that a big hole in the printer side and a switch soldered on the EEPROM write enable could not solve :)
When I put for the first time my hands on a PlayStation, I liked very much the Sony controller. So I tried to find informations about the communication protocol between joypad and console. I found nothing.
So I borrowed an oscilloscope (my Zeroplus LAP-C arrived years later) and tried to reverse engineer the protocol.
This was a test program to help me in the reverse engineering, because the 2 channels of oscilloscope were not enough.
The program, with the aid of a simple hardware interface connected to then PC parallel port, can generate a data sequence on any output pins while reading and recording status of every controller signal
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Out there…