which EPROM eraser and programmer?

[drakke]

I am building a 8088 single board computer (using the Walter Fuller book) that uses 27C256-20 32Kx8 EPROM chips that I need to program.

http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?search_type=jamecoall&catalogId=10001&freeText=27C256-20&langId=-1&productId=39722&storeId=10001&ddkey=http:StoreCatalogDrillDownView

What EPROM eraser and programmer will I need?

If these can be used in other projects I would like to get one with reasonable quality but if they are not particularly useful (this is a pretty old design) then I would like to get something cheap.

Thanks.

[rsjsouza]

A programmer is the popular TL866, even reviewed by Dave.

EPROM erasers can be anything, even the sunlight. For a good selection, there is a lot of dirt cheap ones on eBay but I can't attest for their quality (although I am unsure if you can go really wrong with a timer and the correct UV wavelength light bulb).

[Mechanical Menace]

Personally I'd spend that little more on EEPROMs instead of EPROMs. Less hassle tbh. Plus it may actually be cheaper getting higher capacity EEPROMs and just not using the extra address and/or data lines.

As for programming do you not have anything about you could repurpose for the job? Say an Arduino? Or if you have a PC with a parallel port you could check out something like this

EDIT: The Hackaday article links go nowhere, but some time spent on Google should find you something.

[smjcuk]

+1 for EEPROMs. I spent two years of my youth trying to build a Z80 SBC and most of that was erasing EPROMs after stupid mistakes. Never ever again.

[drakke]

+1 for EEPROMs. I spent two years of my youth trying to build a Z80 SBC and most of that was erasing EPROMs after stupid mistakes. Never ever again.

I'm sold. Can I replace the 27C256-20 with a 28C256?

http://www.futurlec.com/Memory/28C256.shtml


27C256-20
200ns access time
20 mA Active current
100 uA Standby current
28-pin Dual-in-line package

28C256
150 ns access time
50 mA Active Current
200 uA CMOS Standby Current
28-lead PDIP

I also saw this which seems to indicate they are compatible:
http://electronics.stackexchange.com/questions/57857/replacing-27c256-with-28c256-how-to-wire-we

I am a beginner, so anything I missed?

Thanks.

[smjcuk]

Occasionally there is wait state logic for memory access if the CPU is faster than the memory device so you'll need to check timings etc on both the CPU and the EEPROM datasheet. I'm rusty as hell on that so I'd wait for further advice. However its faster than the 27C256 so I doubt there will be problems if it's a proven design.

Also check the programming voltages for the EEPROM as some devices have different voltages for writes/erases.

[Mechanical Menace]

Occasionally there is wait state logic for memory access if the CPU is faster than the memory device so you'll need to check timings etc on both the CPU and the EEPROM datasheet.

Given the vintage I'd be surprised if even slow ROMs aren't faster than the 8088.

I'm rusty as hell on that so I'd wait for further advice. However its faster than the 27C256 so I doubt there will be problems if it's a proven design.

Apart from the waiting for further advice +1. If it doesn't work you have something to fix which is a learning exercise in itself.

Also check the programming voltages for the EEPROM as some devices have different voltages for writes/erases.

Which would only really be a problem with a DIY programmer...