Was going to try a 16K ram internal conversion. Does this chip not exist or not available used or new?
Winbond W24129A
Equivalent available?
Or should I just get a 32K? (and tie to GND A12 A14)
16Kx8 DIP SRAM Unavailable?
16Kx8 DIP SRAM Unavailable?
Last edited by gammaray on Tue Mar 21, 2017 2:44 am, edited 3 times in total.
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Re: 16Kx8 DIP SRAM Unavailable?
I have never seen a DIP 16KByte Ram chip. Common sizes are 2, 8, 32, 128, 512 KByte.
So use a 32K chip (or 2, like me
)
Siggi
PS: see also:
http://www.zx81.de/english/32k-rame.htm
So use a 32K chip (or 2, like me
)Siggi
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PS: see also:
http://www.zx81.de/english/32k-rame.htm
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Re: 16Kx8 DIP SRAM Unavailable?
Forget about 16k byte static RAM chips. I'm not saying that they were never available, but I don't remember seeing one.
The size of memory chips is actually determined by how easy and cost effective it is to make a matrix of memory cells on a piece of silicon. Hence the range given by Siggi above.
All the microcomputer systems that I have played with or know about have either used two x 8k bytes SRAM chips to get 16k bytes (or a greater number of smaller chips), or in more recent times, a larger 32k byte SRAM chip. The 32k byte SRAM chip solution has been the cheapest and easiest way for some time now.
This thread has links to three different guides, all of which use 32k byte SRAM chips to provide a 16k byte internal upgrade
Mark
The size of memory chips is actually determined by how easy and cost effective it is to make a matrix of memory cells on a piece of silicon. Hence the range given by Siggi above.
All the microcomputer systems that I have played with or know about have either used two x 8k bytes SRAM chips to get 16k bytes (or a greater number of smaller chips), or in more recent times, a larger 32k byte SRAM chip. The 32k byte SRAM chip solution has been the cheapest and easiest way for some time now.
This thread has links to three different guides, all of which use 32k byte SRAM chips to provide a 16k byte internal upgrade
Mark
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ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
Re: 16Kx8 DIP SRAM Unavailable?
62256 is used typically (256 kBit/ 32kByte) - price should be around 1-2 EUR/USD depending on supplier.
If you just want 16k you should hardwire A14 to Vcc or GND - doesn't matter.
Don't know why you want to fix A12 for a 16k RAM.
The address lines may be swapped in any order as same as the data lines but it is not recommendable in general as it may confuse others (and yourself).
If you just want 16k you should hardwire A14 to Vcc or GND - doesn't matter.
Don't know why you want to fix A12 for a 16k RAM.
The address lines may be swapped in any order as same as the data lines but it is not recommendable in general as it may confuse others (and yourself).