25LC256 eeprom

I am busy with an embedded web server, based on the TCP Stack 3.75.7e from Jorge.

I am using the PIC18LF2620, ENC28J60 and 25LC256 eeprom. I dont need a level shifter as the SPI is all 3.3Vdc.

Can I run the eeprom with Vcc=3.3Vdc without effecting the frequency that the main stack code uses. Also, can all the pins on the eeprom operate with 3.3Vdc?

Thanks
Michael

My next kit is very similar, although I'm running the EEPROM at 5V.
According to the 25LC256 datasheet the maximum FCLK is 5MHz at 3.3V and 10MHz at > 4.5V
All the pins will work down to 2.5V
Jorges stack is excellent, nice fellow too.
Is your board homemade or a kit?

My board is homemade. I sat for hours designing the tracks and only had the fascility of a single-sided PCB manufacturer, for proto type (it was free). I shall get the proper pcb (double sided) made when Im ready.

It was only about 2months later that I came across Jorge's website and all his projects. i almost fell off my chair to see the various circuits, which were so similar to mine. Mine is almost the same as the eip-10T project. I was designing mine originally using the PIC18LF252, however I just received my PIC18LF2620 samples today

Can you run the eeprom at 5Vdc and still use the SPI with 3.3V signals?

Well then, I've been trying to recruit a handful of members to help with my Ladybug design. I try to make it worth their while. Search for Ladybug on these forums and contine a thread I'll post all my designs there. I am going to have production qty PCBs made. I have a working handwired prototype minus the I/O section. And PCB artwork has been started.
The ENC28J60 designs never stray far from the Microchip reference design.

Can you run the eeprom at 5Vdc and still use the SPI with 3.3V signals?

Click to expand...

Good question, not sure.

I shall have a look at that and let you know.

ya I wonder if u can run the eeprom at 5v and use the 3.3v signals. Anyone else know??

I never have tried it, but on page 2 of the datasheet, it states the high-level input voltage needs to be a minimum of 0.7Vcc, so 3.5v for 5v.

I just read that in the datasheet aswell. Well that explains it all.

Thanks
Mike