More information can be found on the 27C801 eprom d atasheet. The problem is just to do this for 8 * 1024 * 1024 = 8388608 addresses. To write a byte in EPROM simply select the address via pins A0, A1, A2 … and so on put the byte to be written in Q0 pins, Q1, Q2 … etc, and give a pulse with a high voltage ( 13V) in the Vpp pin. And it’s actually even easier to program than flash memories. Write flash memory is not trivial, there is a certain algorithm, but still is a relatively simple process. In 2014, I fixed Mega Drive cartridge using a BIOS chips found in scrap. Even the Chinese ones (It actually depends on the place, here you can pay overpriced from some scumbag or try to import and probably be taxed).Įverything has a cost-benefit ratio and Makers/Hackers are always creating super useful tools with cheap materials. Okay, but then why is not everyone making their own repros? Because a programmer is not so cheap. Swap the cartridge ROM with the programmed ROM.Burn a EPROM with the desired ROM file.Find a boring game cartridge (sports specially).So what? I made this post to prove anyone with an Arduino Mega and some spare components can burn a EPROM for cheap. People should not overprice something they are stealing anyway. The problem is that they are sold usually at prices comparing to those of original untouched cartridges.
Searching for games I found a lot of repro cartridges (Cartridges with the ROM swapped) being sold at local second hand selling websites. But it only came with a bootleg Mortal Kombat cartridge. The client software, written in Python, can be used as a terminal application or executed with a REPL-like interactive interface - "handy to peek and poke at specific addresses," van Zijst explains.Recently I acquired a SNES. Using two daisy-chained shift registers to expand the Arduino's input/output capabilities, van Zijst ended up with a programmer boasting a five-command protocol: read and dump, which read a single address or the entire contents of the EEPROM respectively write and load, which write a single byte or a stream of binary data respectively and reset, which resets the Arduino in case of error. Van Zijst's solution: a shield add-on for the Arduino Uno which includes a quick-change zero insertion force (ZIF) socket compatible with the Microchip AT28C256 EEPROMs chosen for the project. The act of writing, or 'blowing', data to an EEPROM requires a dedicated programming device, which are relatively specialised machines - and, thus, expensive. "In contrast to most newer EEPROMs they have parallel input and output pins for address and data, making it trivial to read from."
#Arduino eprom programmer serial#
"These chips tend to be much larger and expensive than their modern serial counterparts that have largely replaced them," van Zijst explains - but there was a good reason to select the vintage designs for his projects.
Today, EEPROMs - and EPROMs - are rarer, for a good reason. Both, of course, were an improvement over PROMs, write-once read-many devices which needed to be discarded if any upgrades or modifications were required. A common sight on vintage hardware, EEPROMs are surprisingly chunky DIP-packaged chips which upgraded the older EPROM designs in being erasable in-circuit using nothing more than an electrical signal - contrasted with EPROMS, which needed the chip inside to be exposed to strong ultra-violet light from a dedicated eraser through a quartz window in the package.
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