Yes, Mark. The chip does have an CS NOT. It is held high (+5V now instead of 3.3V) so I have to do something there also until I get the new boards. I don't want to order new boards until I prove all circuits/timings etc on this one. I thought of diodes in series on that pin. Think that can work? ----- Original Message ----- From: "Mark Rages" To: "Microcontroller discussion list - Public." Sent: Friday, January 19, 2007 11:49 PM Subject: Re: EE: A dumb mistake. > On 1/19/07, Rich wrote: >> Hi guys: >> I stupidly put 5 volts to a 3.3 volt part. I missed it in the checking >> and the PCB is fabbed. I thought of lifting the pin (can't cut the trace >> because it is an internal layer) and knocking down the voltage with a >> zener glue-on. I hope the zener impedance will be low enough. The part >> is an EEPROM. Has anyone had any experience with this type of fix? I >> will get new boards for production but I don't want to spring for another >> 300 bucks for a test board. I confess to stupid things from time to >> time. > > It will probably work, but you'll need to add a 50K resistor to ground > to make a bit of current go through the zener. > > Does the EEPROM have chip enable inputs that are fixed at 3.3V? You > could leave Vcc disconnected and power through the protection diodes > on those inputs. Not a long term solution, but it might get you by > until your next board rev. > > Regards, > Mark > markrages@gmail > -- > You think that it is a secret, but it never has been one. > - fortune cookie > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist