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Is there any way to use two flash chips ?

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nikki81

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I have just been thinking if there is any way to use 2 flash chips on a tp-link td-w8970 one with the stock firmware and one with openwrt on and a switch to select between them. I have found this circuit diagram will it work ?



Nikki x
 

Pommie

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Most Helpful Member
It should work in theory. However, in practice it will only work when the device is switched off. In fact, if you happen to switch when a write is taking place you could mess up one or both chips.

Mike.
 

Mikebits

Well-Known Member
Check out 1 to 2 decoder chips. I am sure you can find the right logic. The Diode will cause a violation to the flash VIH spec.
 

Pommie

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Most Helpful Member
The minimum input high voltage is VCC x 0.7 = 2.1V. The forward voltage drop of that diode at 1.5mA is around 0.2V. Shouldn't be a problem.

Edit, I'd be more worried about it being switched when on. Is the /WP pin tied low?

Mike.
 

Mikebits

Well-Known Member
I just assumed the standard .7v drop. I suppose from the diode data sheet the spec is ok. They do have single 1 to 2 decoder IC's which would be much less parts.
 

Mikebits

Well-Known Member
Edit, I'd be more worried about it being switched when on. Is the /WP pin tied low?
I would change the switch to a jumper plug.
 

nikki81

New Member
thank you. I think I need to get my breadboard out and do some experimenting. Using a jumper plug is a good idea !

Thanks Nikki
 
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