Go Down

Topic: Writing/reading to a CMOS EPROM? (Read 3399 times) previous topic - next topic

robitabu

Hi, I have to say I am relatively new to electronics but I'm sooo curious :-)

Well, I've got an old MX27C2000 (datasheet: http://www.datasheetcatalog.org/datasheet/macronix/MX27C2000PC-35.pdf ) 2MBit CMOS EPROM at hands and I'm willing to learn about reading/writing stuff with Arduino to external memories. I'm wondering if it could be done with this chip.

Datasheet states it's a "One time programmable read only memory". I thought BIOS chips were CMOS EPROM as well, so I thought it had to be programmable more than one time only. Anyway, I should still be able to read data from it.

I've seen there's no mention about CMOS EPROM programming in the playground, only stuff about EEPROM. What am I missing?

Any hints on the first steps I should learn about will be much appreciated :-)

Cheers,
  Roberto

robitabu

Ok, I give up with the writing stuff, it's clear to me now that it can't be done, my first assumption was wrong.

Still I'm willing to try and read from it. I wonder what approach should I investigate first.

Grumpy_Mike

Quote
Datasheet states it's a "One time programmable read only memory".

They were like the UV erasable ones but didn't have a transparent cover.

Quote
I wonder what approach should I investigate first.

Use output shift registers to generate the address lines, and input registers to read the data lines. Then use the other arduino lines to control the chip enable. Then write a sketch that wiggle these lines like it says in the data sheet and send the results down the serial line. It won't be fast but fast enough to read what you want.

To program them you have to arrange signals to switch high voltages on some pins.

Go Up