AVR-Chat

Hello,
  I would like to add some external SRAM to an existing project and 
would like to know of what pitfalls I should avoid. I purchased the 
STK501 development board and read the manual about interfacing 
external SRAM to an ATmega128 chip. The manual was pretty specific 
about what type of SRAM should be used. I was wondering if people 
have had success with other types of SRAM not mentioned in the 
manual. Speed isnt really an issue. Operating current is an issue 
since I would like to keep it as low as possible. Any help or hints 
would be great.

TIA
Draper Palu

At 07:47 PM 7/19/2004 +0000, dpalu2 wrote:

>Hello,
>  I would like to add some external SRAM to an existing project and 
>would like to know of what pitfalls I should avoid. I purchased the 
>STK501 development board and read the manual about interfacing 
>external SRAM to an ATmega128 chip. The manual was pretty specific 
>about what type of SRAM should be used. I was wondering if people 
>have had success with other types of SRAM not mentioned in the 
>manual. Speed isnt really an issue. Operating current is an issue 
>since I would like to keep it as low as possible. Any help or hints 
>would be great.

Just about any SRAM will work, as long as it's fast enough.

But you don't have to use it through their SRAM interface. 
You can latch and set the address through I/O port bits, or even serial/parallel latches. There's more than one way to store data, but if you need speed, you're pretty much stuck with the conventional system.

--- In AVR-Chat@yahoogroups.com, "Lasse Madsen" <lm@e...> wrote:
> Hi Draper,
>  
> I have tried alot of different SRAM on the ATm128 both in different 
size
> and speed requirements. My opinion is that you can add what ever you
> have in your drawer 
> And it will properly work as indented.
>  
> Also have a look at FRAM they are the hottest things around at the
> moment .

It seems that Ramtron is doing the same thing as MAXIM, offering data 
sheets, but not offering chips in a supply chain.  I have a local rep 
who got me some samples, but it took a couple months and they do not 
stock the memory chips.

I imagine that in a year or so, they will be deeper in the supply 
chain, but right now, I would make sure you can get chips before 
getting too far into design.

Dave

>  
> Regards
> Lasse Madsen
>  
> -----Original Message-----
> From: dpalu2 [mailto:dpalu2@u...] 
> Sent: 19. juli 2004 21:48
> To: AVR-Chat@yahoogroups.com
> Subject: [AVR-Chat] adding SRAM to a design
>  
> Hello,
>   I would like to add some external SRAM to an existing project and 
> would like to know of what pitfalls I should avoid. I purchased the 
> STK501 development board and read the manual about interfacing 
> external SRAM to an ATmega128 chip. The manual was pretty specific 
> about what type of SRAM should be used. I was wondering if people 
> have had success with other types of SRAM not mentioned in the 
> manual. Speed isnt really an issue. Operating current is an issue 
> since I would like to keep it as low as possible. Any help or hints 
> would be great.
> 
> TIA
> Draper Palu
> 
>