You'd think it would be easy to find this info but apparently everyone knows what it is but me.
I haven't programmed one in years and I do not remember what kind of chip it is.
A memory refresher would be appreciated.

 

I've seen a couple, 27C256 and 27C512.

 

Thanks. Worked with 27C512 selected.

 

Are you trying to read a an EPROM?

Either selection should work.

If the EPROM is a 27C256 and you select a 512 to read you will get the program twice in the file.

If the EPROM is a 512 and you select 256, you will get the first half of the file. This is where I will read in both, if I'm not sure and inspect the resulting hex files to see if there is repeat.

 

I was trying to read an eprom. It was not working initially with either the 256 or the 512. I then noticed that the start and end address for the buffer were both set to 0. I just made it match the chip addressing for the chip I had selected (the 512) and then it worked.
I suppose I could go back and try doing the same thing but with 256 selected, or just look at the raw hex. Looking at the raw hex will require some jogging of my memory banks to remember what I'm looking at.

Luckily I was able to read the chip, make some changes, and burn a new chip successfully. I'll probably be back to ask more neo-newb questions soon