[sdiy] SRAM Memory Upgrade (Old Sampler) ???

[harrybissell]

Hello Phuture

Yes... it would in theory work. As long as you did not change address lines
during a write cycle.  The best way would be to use some latch for the extra
lines that is disabled during a write (or read).

Grayhill makes a $5 class rotary encoder that has hex output. DigiKey
has it. That could do all your addressing for you, just turn one knob

H^) harry

::Phuture:: wrote:

> Hi people,
>
> Wow, it's been maybe 4yrs since i last was on this list!
>
> So, I've got a question that relates to upgrading memory in a certain breed
> of old casio samplers.
> I'm sure it's impossible to increase the actual sampling time, but I feel
> I'd certainly be able to increase the ammount of banks.
>
> Right now, the sampler uses a single 32k x 8-bit 28-pin DIP CMOS SRAM. This,
> i believe, was the largest possible size in a 28-pin format. Now, hopefully,
> I'd like to install a 32-pin SRAM in it's place, which is organized as 512k
> x 8-bit (16 times the original size). Aside from the top 2-pins on both
> sides of the 32-pin IC, the rest of the pins line up with the original
> 28-pin SRAM.
>
> The difference between the two chips, besides the VCC being on a different
> pin, is that there is an additional (4) address lines....... All other pins
> are compatible with the 28-pin version.
>
> Now, I'm no expert on how memory works.....but from my research it seems
> like adding 4 spdt switches to control the highest 4 address lines would
> give me (binary) access to switch between the 16 banks. Is this correct?
>
> Aside from the additional banks, the newer SRAM would give data retention of
> 10+ years because of an inbuilt lithium battery in the IC.
>
> I'm a little techie, but still need some advise from a pro that can verify
> that this would indeed work, at least theoretically!
>
> Thanks
>
> Ryan (Plutonique9)
>
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