Author Topic: Source of flash chips  (Read 999 times)

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Online veedub565Topic starter

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Source of flash chips
« on: December 15, 2021, 06:47:11 pm »
Does anybody know a legitimate source of the obsolete Sharp LH28F320sktd flash chip. Or an equivalent that is still available ?

Many fakes to be found, may or may not work. Would prefer genuine parts though.
 

Offline tom66

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Re: Source of flash chips
« Reply #1 on: December 15, 2021, 07:08:23 pm »
Looks like a fairly generic 56 TSOP flash.

You could probably find A.N.Other flash memory device with the same pin out (the 56 TSOP package is fairly standard) and it'll work.  You may even be able to go up in size, provided all of the address lines are connected. (If the unused address lines float, this could cause memory errors unless you can mod-wire the board to tie them to ground.)
 

Online veedub565Topic starter

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Re: Source of flash chips
« Reply #2 on: December 15, 2021, 07:56:15 pm »
I've found a few TSOP56 devices, all of them have much much more capacity than this one. So I wasn't sure if they would work.
 

Offline ANTALIFE

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Re: Source of flash chips
« Reply #3 on: December 15, 2021, 10:15:48 pm »
Try using https://www.netcomponents.com/ and tell us how it goes ;^)

Offline tom66

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Re: Source of flash chips
« Reply #4 on: December 15, 2021, 11:07:22 pm »
I've found a few TSOP56 devices, all of them have much much more capacity than this one. So I wasn't sure if they would work.

You have to realise capacity is only there if it is addressed.

If the device never addresses beyond the 16Mbit or whatever that device is, then you can fit a 64Mbit part and it'll behave just like a 16Mbit one, provided you program it with the same image.  The CPU will not know or care that such a large device is fitted.

You could have issues if the additional address lines aren't grounded, so you may have to check a schematic (if available) or meter out signals to see if they go to the CPU.  In my experience it's pretty common for engineers to connect all of the address lines of their flash chip to the processor, because they may not know in advance what size they want to fit.  However, this isn't guaranteed.  If you're steady with soldering you could connect the redundant address lines to ground and program the image into the zero page of the flash.
 
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Online veedub565Topic starter

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Re: Source of flash chips
« Reply #5 on: December 16, 2021, 07:57:56 am »
Thanks Tom, I did not know that before. So as long as its TSOP56, the correct voltage and pinout then I should be good to go. I'm ok with soldering so no probs doing that if required. 

I think the usual places like Mouser, Farnell etc still stock that package.
 


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