EEPROM memory and crystals

[gonzcaal]

someone could explain because you put a bridge to the crystals for programming the EEPROM.


As what the crystals?


I want to learn to program them only with a clip eeprom, and I do not want desoldering memory.


thank you very much.

[PremierD]

AKA .... https://www.youtube.com/watch?v=aJAZHPqEUKU

[Rerouter]

The crystal, or "quartz crystal oscillator" is the clock of the device that would normally talk to the eeprom,

By shorting it out you prevent that device from waking up, for most devices this leaves most of its pins "open circuit" allowing you to read the eeprom without it interfering,

There are 4 main types, 2 pin crystals, 4 pin crystals (both tend to be in the silver package), resonators, and clock drivers,

the 2 and 4 pin style can be shorted, or if in doubt use a 100 ohm resistor, resonators must only be shorted by a resistor, and clock drivers cannot be touched, instead you would look for the devices reset pin.

[rocko]

if you do incircuit/onboard pogramming of eeproms, have always to short crystal.
eeproms like 25xxx and 95xxx you can read/write for sure without destroying data
but for other eeproms it is always better to desolder it and then to do the job
(to avoid the data to be damaged through reading process)