is using a similar construction technique by forming the legs of the EPROM out of laminated plywood. Even at footstool scale, the 555 is still relatively tiny. A few years ago, they built a 555 footstool that was scaled up about 30 times its normal size. ’s coffee table was inspired by an earlier build by the geniuses at Evil Mad Scientist. It’s a huge, scaled up version of a UV erasable EPROM with an infinity mirror in place of the fused quartz window. Posted in classic hacks Tagged eeprom, eprom, firmware, firmware dumping, PROM, romĮither in need of a coffee table or suffering a severe lack of upscaled electronics, just finished up a great build for his living room.
#CHEAP EPROM PROGRAMMER SERIAL#
All the data was dumped over a serial interface, and in just a few seconds, had 32768 bytes of ancient data that made this old synth tick. After that, it’s just a matter of stepping through every address according to the timing requirements of the PROM. Interfacing the PROM is as simple as connecting the power and ground, the address lines, data, and the signal lines.
He found the LPC2148, which has a nice USB system that can be programmed to dump the contents of a PROM over serial. The old EPROMs in this machine have 5v logic, so needed to find a board that had a ton of IOs and 5v tolerant inputs.
#CHEAP EPROM PROGRAMMER CODE#
It turns out building a 27-series PROM dumper is pretty easy, giving an easy way to dig into the code on this machine. There wasn’t an EPROM programmer around to dump the data, but did have a few ARM boards around. In an attempt at reverse engineering, decided to dump the EPROMs and take a peek at what made this synth work.
Being so rare, there isn’t much documentation on the machine. This was one of the first wavetable synths available, and it’s exceptionally rare. recently came across a very old synthesizer from a defunct West German company. Posted in classic hacks Tagged eeprom, eprom, flash, hackaday.io, sram, supercapacitor This project makes us think of another where an LED may have been supplying keep-alive power to some volatile memory. It’s not the best solution in every case, but it is certainly interesting, and could be useful for more than a few vintage computing enthusiasts. Also, EEPROMs have a write lifetime SRAMs can be written to an infinite number of times. For strange EPROM sizes, old SRAMs abound, but a suitable Flash chip in the right package (and the right voltage) might be very hard to find. This is accomplished by a few LEDs in series, and a 0.1F 5.5V supercap which keeps the SRAM alive when the power is off.Īs for why anyone would want to do this when modern technologies like Flash can be found, we can think of two reasons. The circuit requires a small bit of electronics tucked between the EPROM socket and the SRAM chip just enough to turn the 12 Volts coming from the EPROM programming pin to the 5 Volts expected from the SRAM’s Write Enable pin. Capacitor technology has improved dramatically since the 1980s, and by using a supercap and one of these RAM chips, has created a substitute for a 27-series EPROM that keeps all its memory alive for days at a time. SRAM is completely unlike EPROMs or Flash, in that it requires power to keep all its bits in memory. ’s creation is a mostly non-volatile memory built around an old 62256 32k SRAM. wanted an alternative to these 27xx-series EPROMs, and found his answer in supercapacitors.
Times have changed and now we have EEPROMs, which can be erased electronically, and Flash, the latest and greatest technology that would by any other name be called an EEPROM. The nature of these EPROMs meant you could write to them easily enough, but erasing them meant putting them under an ultraviolet light. Back in the days of old, computers used EPROMs to store their most vital data – usually character maps and a BASIC interpreter.
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