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So I'm going through the datasheet for a device by Atmel (AT91SAM) and it shows the followings:

This SMC is capable of handling several types of external memory and peripheral devices, such as SRAM, PSRAM, PROM, EPROM, EEPROM, LCD Module, NOR Flash and NAND Flash.

So that's good as I can get SRAM from Digkey, however there are many types: SRAM selection on Digikey.

Which one is the right one? Perhaps several? I remember doing these exercises in the university all the time in micro-computer class, but we never talked about which type of exact memory we're hooking up to the 8086 micro :) I'll appreciate help clearing this up. BTW I see that the bus width is just 8bits so that will also help minimize the selection but the type is still needs determining.

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  • \$\begingroup\$ You need more than just that blurb to know. \$\endgroup\$
    – Ignacio Vazquez-Abrams
    Commented Sep 5, 2014 at 20:43
  • \$\begingroup\$ @IgnacioVazquez-Abrams where do you suspect that they hide the detailed info? \$\endgroup\$
    – user34920
    Commented Sep 5, 2014 at 20:44
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    \$\begingroup\$ In the section that talks about memory in detail. \$\endgroup\$
    – Ignacio Vazquez-Abrams
    Commented Sep 5, 2014 at 20:48
  • \$\begingroup\$ Have you tried searching the web for "AT91SAM sram"? I had a quick skim, and there were several pages which seem to be potential answers to your question. Those pages might give you specific part numbers, which in turn may give both specific parameter-values for your component search, and how to configure the memory controller. \$\endgroup\$
    – gbulmer
    Commented Sep 5, 2014 at 21:08
  • \$\begingroup\$ Somewhere in the datasheet and/or reference manual for the AT91SAM it will (or should) explain in great detail how to connect various types of memory to it. That should give you a good starting point when working out which type/s to use. \$\endgroup\$
    – markt
    Commented Sep 5, 2014 at 22:33

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The peripherals listed there typically have "asynchronous" busses -- that is, the simple and familiar type with address lines, data lines, and a couple of control and latch lines. This means that the SMC is not meant to work with SDRAM, DDRAM, or other subspecies of synchronous dynamic RAM: it's meant to work with regular ol' asynchronous static RAM, so that's what you'll probably want to look for.

You can also use PSRAM (Pseudo-Static RAM) with the SMC. PSRAMs are dynamic RAM chips with a controller tacked on that imitates an asynchronous RAM, and takes care of all the messy refresh chores for you. Since they're dynamic RAM inside, they can be very large and relatively cheap. The downside is that they're also slow, like dynamic RAM.

You probably don't want dual-port or quad-port RAM. If you needed it, you would almost certainly be looking for it specifically.

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