Atxmega + SDRAM - Page 1
Forum section: electronics / beginners

author: Cyborg666
author_rank: Newbie
timestamp: April 22, 2014, 09:22:28 am
content: Hi!I'm working on a project with my brother, in which he will do the electronics, and I will do the programming.We need quite a bit of RAM for this project, and I was wondering if it's possible to use this micro in conjunction with this RAM?http://www.mouser.com/ds/2/36/Atmel-8385-8-and-16-bit-AVR-Microcontroller-ATxmeg-259120.pdfhttp://www.mouser.com/ds/2/12/64M-AS4C4M16S-7450.pdfDoes anyone have some tips on how to hook them up properly, or perhaps a link to a guide or something?

author: amyk
author_rank: Super Contributor
timestamp: April 22, 2014, 10:54:08 am
content: That SDRAM specifies no minimum clock frequency (they usually have one), but it must be refreshed at least every 15.6us. Either way, interfacing SDRAM to an 8-bit MCU is not an easy task, althoughit can be done.

author: Psi
author_rank: Super Contributor
timestamp: April 22, 2014, 11:14:07 am
content: The xmega has an external SRAM/SDRAM bus, so there should be no problem using SDRAM.However you will need to make sure the SDRAM IC timing is within the xmegas external bus timing.

author: David Hess
author_rank: Super Contributor
timestamp: April 22, 2014, 08:22:47 pm
content: Quote from: amyk on April 22, 2014, 10:54:08 amThat is actually FPM or EDO asynchronous DRAM and not synchronous DRAM which was not used in 30 pin SIMMs. It is being accessed using programmed I/O so it is only suitable for use with emulation which is exactly what the author is doing.Cyborg666, that microcontroller only has an 8 bit wide SDRAM interface so it should work but half that that 16 bit wide memory would be lost.

author: theatrus
author_rank: Frequent Contributor
timestamp: April 22, 2014, 08:29:51 pm
content: Do note that AVR-GCC does not work in the hybrid addressing mode required to access all of your memory on the xMega. You can do assembly-assisted-copying, or use IAR or another compiler which does support it.

author: janoc
author_rank: Super Contributor
timestamp: April 22, 2014, 08:31:01 pm
content: Quote from: Psi on April 22, 2014, 11:14:07 amThere is an appnote on it:http://www.atmel.com/images/doc8058.pdfHowever, XMega doesn't have a dedicated SDRAM controller, the appnote only shows how to drive the SDRAM electrically.All the initialization and everything else that an SDRAM needs is up to you to do in software (the refresh can be handled by the EBI on the chip). Not an easy job for an 8bit micro, not to mention that you would block most of the available I/O with it.I would probably look for something beefier if SDRAM is needed - e.g. an ARM.

author: Cyborg666
author_rank: Newbie
timestamp: April 23, 2014, 11:53:00 am
content: Quote from: wilfred on April 22, 2014, 10:57:04 pmWe're trying to make a digital audio delay pedal for guitar players.It's supposed to have a feature in which you can record a sample of about 40 seconds - in stereo.I've only worked with arduino before, and have mostly done regular PC-programming. So I'm a bit worried about how hard this will be.Do you have any suggestions on which controller/memory would be suitable for these tasks?

author: Tubis
author_rank: Newbie
timestamp: April 23, 2014, 12:58:14 pm
content: Hi. Im the other part of this experiment. I understand nothing about programing but i can hook up the electrical and make pcb.We selected the atxmega because it had adc and dac and enought pins for a number of external controls in form of potentiometers pushbuttons, rotary switches and to control some leds and analog bypass line. The project is to produce something like this:http://www.bossus.com/gear/productdetails.php?ProductId=958&ParentId=255Would this memory work better?http://se.mouser.com/ProductDetail/ISSI/IS42S81600E-7TL/?qs=sGAEpiMZZMti5BT4iPSEnXRShtGGCFK3TG42wTPCEQU%3dIt looks more pin compatible?