DIY ICSP eeprom programmer?

[Chriss]

Hi!
I thinking about to make a ICSP programmer for eeproms like 24/25/93xx series.
Is there a diy schematics maybe what I don't found after two days of searching on the net?

Or, a better way would be if I could mod my MiniPro TL866CS programmer to
use it for in-circuit r/w of eeproms.
That would be the best think for me.

Is something possible to do?

Thanks in advance.

[amyk]

Schematic? What do you expect to be on the other side? Serial EEPROMs don't need much in the way of wiring, and can be programmed with something as simple as a parallel port and a few wires...

[BradC]

Is something possible to do?

It's often difficult. In powering up the EEPROM to talk to it you often power the associated circuits that drive it which then interfere. If you isolate the power pin, it's not unheard of to get significant loading on the data pins due to clamping diodes in the chip that normally talks to the EEPROM.

I did a couple recently where I raised the VCC leg on the flash and used a home-brewed programmer with significant drive potential to wiggle the data pins, and that worked. In hindsight it would have been faster and easier to just pop the chip and write it out of circuit.

[Chriss]

I know, the best solution is to pop out the ic and put it in a programmer, that method I use the last 20 years.
But I saw several programmer who can do In-Circuit programming of eeproms and I tough there is a way to make
some mod to my existing programmer or to make a simple I.C. programmer so I don't have to pop out the eep.
I was thinking in the meaner of today's modern technology ad maybe there is a possibility, that is why I asked...

I know about the major problems of I.C. programming, but I had a hope to figure out something simple and nice. 

[NorthGuy]

If your EEPROM is connected to an MCU, the MCU is most likely programmable in-circuit. Then the best way is to program your EEPROM through the MCU.

I have a tankless water heater. They distribute their firmware in a small PCB with a flash chip. If you do this, you always can take your EEPROM out for re-programming and replacement.