6502.org

Hi,

I am an avid user of my trusty Acorn Electron computer and would like to start programming it using the Forth programming language. I have downloaded a ROM image from the web, but I am uncertain of the type of ROM I require and how to burn the image to it via a PC. Does anyone have any suggestions?

Also does anyone know if any of the books in the book list are available in PDF format under the Open Source banner. I have three in the list and would convert them into PDF, but I am uncertain on how to contact the Authors to get their permission to share it on the web.

Thanks for any help.

Regarding the type, there are various possebilities. In most cases it is a 27xx type, next possebility 25xx. The xx depends on the size of the file (if it is a BIN file):
2048 -> 16, 2516 or 2716
4096 -> 32, 2532 or 2732
8192 -> 2764
16384 -> 27128

Then you need to find someone with an EPROM programmer. Most programmers can handle a BIN file.
I live in the Netherlands, a bit far away from Arizona.

Thanks for the info. The ROM image that I have is 16kB in size and I assume that it is in a binary format. Should I get a 2716 EPROM or a 2732 to allow for expansion as my own version of Forth expands? Also are there any cheap EPROM programmers for the hobbist, or even plans so that you can build your own?

The suffix of the ROM chip indicates how many kilobits can be stored in the ROM. So if you have 16384 bytes, that's 131072 bits, or, 128Kbits. Hence, you'll need a 27128 or 25128.

Things tend to get a bit screwy for megabit-sized devices, but it's doubtful you'll need something that large for a 65xx-based project.

Hope that disambiguates things.

There are surely a lot of cheap ROM programmers in the market. And they are easy to be built by yourself,if you have some experience. I suggest you should use 28128 or 28256.(29xx series will also OKay). Because these devices are Flash-ROM. They can be reprogrammed many times.