Pabloz wrote:OK then i will forget my idea […]
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Tiido wrote:The chip is not in system programmable via external means, connecting such a thing to a non powered card will at best do nothing and at worst kill the card's IO pins connected to the EEPROM or the programmer itself as it tries to partially power the entire card. Connecting it to a powered card will only fight with the IO pins and you still risk damaging them.
OK then i will forget my idea
so only hope is to gently remove the chip from the working board
then read it.
then remove the chip from the other card and flash it.
but it is difficult to remove with just soldering iron..it has 8 legs. and i dont want to burn it
Here are some tips for doing that. I've done it a lot, mostly for routers etc. get some liquid flux (preferably the no-clean type) and desoldering braid. Also get either tweezers or a small screwdriver, the kind that you use for eyeglasses. Make sure the screwdriver is sharpened, you will be using it as a wedge. If you have someone helping you it's easier as you can have the second person use the tweezers; if you're alone and only have your 2 hands you will have to use the screwdriver instead.
Apply a generous amount (but not excessive) of flux over the pin/pad solder connections on both sides of the chip. Heat your soldering iron just enough to melt the solder. Place a length of the desoldering braid over the pins on one side in such a manner to cover all of them, then press it down with the side of your soldering iron tip. Hold the tip there until the solder melts and starts wicking into the desoldering braid (you can tell as the braid changes color from copper to silverish). Lift the tip and the desoldering braid, cut the length of the braid that is now saturated with solder, place the braid back over the pins, repeat until you don't get any more solder wicking up in the braid. Do the same on the opposite side of the chip.
Now, either have the other person grab the sides of the chip (the ones without pins) with the tweezers and gently pull up, or insert the tip of the screwdriver under the chip between it and the PCB, and apply pressure down so that the tip pushes the chip up from underneath. Put again the tip of the soldering iron over the pins on one side this time without the braid so you heat them up uniformly until all solder is melted on that side. The tip of the screwdriver (or tweezers) should lift all pins on that side at once. Don't lift more than 1mm, or just enough that the pins don't touch the pads anymore. Do the same on the opposite side and the chip should pop free.
(edit) don't be afraid to burn the chip, that won't happen unless you set your soldering iron too hot and take a really long time with it in contact with the pins. Those chips are made to withstand reflow, which heats the whole chip at the temperature that melts solder for 10 seconds or so. They are specifically designed to go through such treatment without harm.
I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O