The 13 volts are provided by a boost module, but possibly a 12 volt supply can be used (I did not test, may be you can ).
This makes it eadsy to attach and remove the Eprom. I soldered the circuit on a prototyping shield with a ZIF socket. I used a simple jumper and manually change Vcc when needed.
Schematic for the EPROM burner with Arduino.Īlso, it should be noted the Eprom needs to be fed 6V when being programmed. However, I did not buy an Arduino only to program memories, I have some here at home I use to all kinds of things.īelow is a schematic I came up with for the programmer: Why not also try EPROMs? Also, Arduinos are super cheap (Ebay/Ali express). I’ve used Arduino to program other kinds of memory. 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.
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. Repeat this procedure for the next address and corresponding data.Recently I acquired a SNES. After providing the required programming voltage, press switch S1 to program the data at the desired address. Select the programming voltage using jumper J1 and set the programming address and data value using switches SW1 and SW2, respectively. Then connect the power supply to provide regulated 5V DC to the circuit. Now insert the EPROM chip into the 24-pin ZIF socket and slide switch S2 as per EPROM. To begin with, first read the programming voltage written on the EPROM. IC1 is used to provide +5V regulated supply to the circuit. The programming voltages of 25V, 21V and 12.5V are generated with the help of zener diodes ZD1, ZD2 and ZD3. The secondary output is rectified by diode D1 and filtered by capacitor C1. The AC mains is stepped down by transformer X1 to deliver 30V, 250 mA from the secondary. The address and data for the EPROM (ZIF SOCKET) are set by using DIP switches SW1 and SW2, respectively, whose pins are initially pulled high via 10-kilo-ohm resistors. The programming voltage required for an EPROM is sometimes written on its body. Before applying the programming pulse to the EPROM, select the programming voltage (25V, 21V or 12.5V, as specified by the manufacturer) applied to pin 21 of the ZIF SOCKET by using jumper J1. LED1 glows to indicate the application of the programming pulse to the EPROM. EPROM is inserted into the ZIF SOCKET for programming. When push-to-on switch S1 is pressed, IC2 generates a 50ms pulse, which is given to the program pin 18 of the ZIF SOCKET through switch S2. The circuit uses timer NE555 (IC2) wired as a monostable. Here is a low-cost EPROM programmer circuit to program binary data into 27 EPROMs. The programmer devices required for programming the electrically programmable read only memories (EPROMs) are generally expensive.
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