Re: SRAM with multiplexed bus

Nov 15, 2004 11 Replies

Thanks for all the replies. I am aware of the PSD devices, but I just need SRAM. It indeed strange, there *seems* to be a market demand for these types of SRAM. Heck, some companies are still making 8k x 8 and 32k x 8 chips for small embedded applications. There must be quite a lot of these applications using muxed buses.



Meindert


True, but it's also a tough market, and Latched EPROMS are not what you'd call at critical mass. They still exist, and in small packages, ( like the 27C520 from Atmel & Winbond ( and Fairchild for a while ) )

The 27LV1026 is a good example of what CAN be done with smarter-bus memory.

Dallas do have a CLK/RAM with 2-4-8K with ALE BUS, but that's not what would be called a generic part.

With the growth of DATA Flash, and the drive now to push up the read bandwidth, multiplexed BUS would be a good solution.

-jg

"Meindert Sprang" skrev i meddelandet news: snipped-for-privacy@corp.supernews.com...

Do

It is not longer a good idea to use "Many mainstream microcontrollers" in applications requiring medium sized SRAMs, since the 0,18u and lower embedded flash processes allows you to cost effectively integrate 32-64 kB of SRAM. The AT91SAM7S series will be available in

32kF+8kR,64kF+16kR, 128kF+´32kR, 256kF+64kR etc. Philips LPC has similar combinations, although the flash size seems to be fixed to 128kB in most parts.

With low cost ARM toolsets around the corner it is maybe time to to move on guys :-)

Best Regards Ulf at atmel dot com These comments are intended to be my own opinion and they may, or may not be shared by my employer, Atmel Sweden.

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Let me see: my application requires appr. 6000-8000 units/year. The Mega162 costs me 2.35 euro, the latch appr. 0.10 euro and the SRAM 0,75 euro. That adds up to 3.20 euro. I haven't had an offer for an ARM type controller for that price yet.

Meindert

I read the datasheet briefly and I vaguely rember a post in this ng about it: does the LPC have no form of code protection?

Meindert

Yes and no. The 2104, 2105 and 2106 variants to not. AFAIK the rest do.

Robert

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I wonder how Philips is going to get some market share with this.....

Meindert

Hi Ulf,

Just so you know, we are looking very hard at these parts in our migration away from horrible legacy 8-bit micros. I'm trying to get managerial permission to port one or two simple projects to ARM in order to pave the way for other projects.

We hate Philips :)

Is there something new coming out soon? If you want to forward me any info, you know my email address...

be

0,75
3,20 Euro * 1,3 = = $4,16. Might work for the AT91SAM7S64 w 16 kB. If you can fit the latch in your design, why complain?
Best Regards, Ulf Samuelsson ulf@a-t-m-e-l.com This is a personal view which may or may not be share by my Employer Atmel Nordic AB

I know. After my post I remembered an e-mail I recently received from our local distributor: 3.16 euro for the AT91SAM7S32 and 4.57 euro for the AT91SAM7S64, both in 100 units. So that's a good and cheap solution.

Well, I can fit it in, but the routing requires as much extra board space as required by the latch and SRAM. And it leaves me no room for expansion of the design. But these new ARM mcu's are just the solution I was looking for. The moment they're available here in the Netherlands, I'll design them in.

Regards, Meindert

as

So having it integrated is worth some money then :-)

No need to wait, the parts are sampling and there is a development board as well..

Best Regards Ulf at atmel dot com These comments are intended to be my own opinion and they may, or may not be shared by my employer, Atmel Sweden.

as

Well, if they're sampled right now, who will guarantee I can run production in 4 weeks (we have very short development times in our small company :-)) ?

Meindert

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