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Topic: RAM, SDCards, Memory (Read 920 times) previous topic - next topic

idover

i've seen a project that allowed an ATMega chip to use an SD card through serial communication... can the chip also use RAM simms?... i have some old ram lying around and if i can use it, that would be fun... i don't really have any need to do so, just to learn..

thanks,
isaac

Cheater

Computer ram usually requires in the order of 200 pins.
Have fun trying to hook it up. :P

Theoretically its possible but more trouble than what its worth.
Best to get some ram chips designed for micro controllers.

kg4wsv

The problem with typical computer RAM is not the number of pins (which is a huge pain) but the fact that most iof it is DRAM, which requires the contents to be constantly refreshed.

For Microcontroller projects you want SRAM, which doesn't require support hardware to maintain its contents.

One trick to get around the number of pins requirement is to use one or more serial in/parellel out shift registers for the address, and 8 pins for the data.

I have seen data sheets for an 8 pin SPI interfaced SRAM, but it does not appear to be in production, as the only place I found to order it wants several weeks lead time and a minimum order of one spool (2500 units, IIRC).

-j

idover

oh well, i have some old computer parts lying about that i'm trying to have fun with... a few simms, a pci modem, hard drives, pci 802.b wireless card, web cam (with an mmc card)... i'm not afraid to scavenge for a bit of fun if anyone has ideas...

as for storage - i am planning to build a simple weather station next week and just wanted to sample and average... i've discovered a couple of good sites:

http://www.arduino.cc/playground/Main/UsbMemory
http://jvcideas.blogspot.com/

my main interest at the moment is serial communication... moving parts don't really excite me (yet) :)..

thanks,
isaac

follower

Quote
as for storage - i am planning to build a simple weather station next week and just wanted to sample and average...

Have you considered EEPROM for your storage needs?

--Phil.

Cheater

Quote
Have you considered EEPROM for your storage needs?

He doesnt have storage needs. He just wants to hook random stuff together. ;)

sirmorris

#6
Nov 18, 2007, 09:32 pm Last Edit: Nov 18, 2007, 09:34 pm by sirmorris Reason: 1
Quote

He just wants to hook random stuff together.


LOL I have the same urge :D

Some memory modules (the 168 pin ones at least) have a serial EEPROM nailed on, ready for the scavenging. If you're confident with an iron, or unconfident but ballsy, then there's a project right there. You only need 4 wires soldered on, and away you go. check:

http://www.dewassoc.com/performance/memory/how_to_ID_memory.htm

look for SERIAL PRESENCE DETECT and have fun!


idover

Quote

He doesnt have storage needs. He just wants to hook random stuff together. ;)


how correct you are, sir!... and to add to the list, i've discovered two usb game controllers, and a PS/2 number pad (my wife is an accountant - and she believes me to be quite the nerd) :)... eeprom is promising, but i've no experience with it... and it appears that using computer ram wholy is out of my league right now, but those that i have are simms for a laptop, which don't seem to have the onboard eeprom ...

i just need to reset and let the rational side of the brain catch up to the creative side!..

thanks,
isaac

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