EEPROM programmer

[CTho9305]

What is involved in making an EEPROM programmer? I want to use it for BIOS flashes. Does anyone have any schematics? Are the BIOS images provided by motherboard manufacturers just the data, or do they include extra information that must be removed?

 

[majewski9]

programming roms is done by machine that physically burns data to the chip. I dont think it is easy to make one so you should just buy one if you really wanted to. It isnt just as easy as that. I am actually suppose to get to burning roms later this quarter I believe so I could shed a lot more infromation on this subject. I do know what the rom burner looks like and I dont think you can simply make one. It also takes an understanding of assembly programming to burn a rom.

 

[dejitaru]

What about those with the glass window?
EEPROMs are rewritable?

 

[CTho9305]

Originally posted by: majewski9
programming roms is done by machine that physically burns data to the chip. I dont think it is easy to make one so you should just buy one if you really wanted to. It isnt just as easy as that. I am actually suppose to get to burning roms later this quarter I believe so I could shed a lot more infromation on this subject. I do know what the rom burner looks like and I dont think you can simply make one. It also takes an understanding of assembly programming to burn a rom.

Well, a PIC programmer is very simple (a small PCB with about $5 worth of parts) - at least, one that goes to the computers serial ports. Is an EEPROM programmer all that different? This could be used to recover from a bad flash, or to play with other crazy EE/CE stuff

 

[Mark R]

Well, a PIC programmer is very simple (a small PCB with about $5 worth of parts) - at least, one that goes to the computers serial ports. Is an EEPROM programmer all that different?

Depends what kind of EEPROM? Microchip do EEPROMs which are programmed in the same way as a PIC.

I suspect though that the EEPROMs used for BIOS images are parallel - in that they have an address bus and a data bus, and assorted control pins. The Microchip devices have a single 2 wire serial port on which erase/program and read commands are issued. The PC only needs to control 2 signals - easily supplied by a parallel port - no other external parts needed (but recommended for reliability).

You really need the programming specification from the EEPROM manufacturer - there are dozens of different types of EEPROM, and they aren't necessarily compatible. I suspect it wouldn't be too hard to build a programmer based around a PIC. The programming protocol is usually very simple - apply a high voltgae to the programming pin, present the address and data, and clock the write pin, repeat.

 

[CTho9305]

Originally posted by: Mark R

Well, a PIC programmer is very simple (a small PCB with about $5 worth of parts) - at least, one that goes to the computers serial ports. Is an EEPROM programmer all that different?

Depends what kind of EEPROM? Microchip do EEPROMs which are programmed in the same way as a PIC.

I suspect though that the EEPROMs used for BIOS images are parallel - in that they have an address bus and a data bus, and assorted control pins. The Microchip devices have a single 2 wire serial port on which erase/program and read commands are issued. The PC only needs to control 2 signals - easily supplied by a parallel port - no other external parts needed (but recommended for reliability).

You really need the programming specification from the EEPROM manufacturer - there are dozens of different types of EEPROM, and they aren't necessarily compatible. I suspect it wouldn't be too hard to build a programmer based around a PIC. The programming protocol is usually very simple - apply a high voltgae to the programming pin, present the address and data, and clock the write pin, repeat.

So I could probably find that info in a datasheet then?

 

[Mark R]

So I could probably find that info in a datasheet then?

Yup. Just be careful, this information is not always found in the datasheet for an individual device. There may be a seperate 'programming specification' sheet for a series of devices.

 

[Peter]

Every single make and model of FlashROM device has its unique programming model. This is what separates good programming machines from the bad ones - not only a wide selection of form factor adapters, but also the electrical flexibility of the circuitry, and most important of all, a huge library of programming algorithms in the software.

Back in the days when we had EPROM or EEPROM, this indeed was a feasible DIY. With FlashROMs, that's pretty hopeless.

 

[Peter]

(dp)

 

[majewski9]

Yeah I am pretty much a novice at burning roms but I do know that EEPROM needs to flashed with UV light. I dont think it is easy to make a UV light flasher from scratch.

 

[Era]

EEPROM. Electronically erasebable prom. So no UV needed, just circuitry to make the erasing and reprogramming.

 

[dejitaru]

Of course you don't need the UV, but it's an easy way to carry out mass erasure.

dig this:
http://www.ai.mit.edu/~vona/bass/bass-details.html

 

[Mark R]

Of course you don't <I>need</I> the UV, but it's an easy way to carry out mass erasure.

I don't think so

EEPROMs are not fitted with UV transparent quartz windows. UV light is ineffective for these as it cannot actually reach the die.

 

[hakadate]

If you are really interested in building an EEPROM programer list your email or My email is btamura@aol.com I will tell you where you build or buy one. It has schematics and software.
It is designed to work in an ISA slot. You could use a 486 computer. The last I heard the cost of the board and parts was about $90. I built one using wirewrap but lost interest before I finished.

 

[CTho9305]

Originally posted by: hakadate
If you are really interested in building an EEPROM programer list your email or My email is btamura@aol.com I will tell you where you build or buy one. It has schematics and software.
It is designed to work in an ISA slot. You could use a 486 computer. The last I heard the cost of the board and parts was about $90. I built one using wirewrap but lost interest before I finished.

thanks, but for $90 I dont think it is worth it :frown:

 

[dmk11]

EEPROM programmer is expensive.. especially the ones that can do different type of chips. I ordering one for my company to be used in our lab and it was a couple thousand dollars.

Different EEPROM have different ways of being programmed. The ones I worked on before usually involves in writing specified patterns in specified address at a few different location (putting it in programming mode to eliminate accidental writing) and then writing to the actual location with the actual data. If you can somehow get direct read/write access to the BIOS chip directly, you can probably do it. But I doubt the OS will let you do this.