Hello I am looking for some memory to use in a project so far I have two candidates. 30pin SIMM memory from a 486 (looks hard to interface!) and a 4mb static ram. The problem is that the static ram only comes in surface mount packages and so I will have to build some kind of adaptor to mount it on a breadboard. The 30pin SIMM is easier from this point of veiw as I can just use a soccet from an old motherboard and solder onto its pins. Info on static ram: http://www.rapidonline.com/netalogue/specs/73-1200e.pdf the packages are: 44-pin TSOP II and 36-pin SOJ 400 is there anywhere that would sell an adaptor for these? or is soldering a posibility? If not is there any info available on interfacing 30pin SIMMs?
I think the most common way of soldering SMT components to the board is to use a solder paste. I believe the process is make a square of paste -> sit the component in it -> put it in a toaster oven -> remove excess paste (between pins). You might also be able to get chip sockets like the ones used on BIOSs?
I just realised those are probably going to be SMT as well though due to the pin spacing. heh. Still, it should prevent frying chips
hmm I found some adaptors but they all seem to be wanting industrial orders and not one off's. I think I will use the SIMM's as I have found a very informative guide on how to use DRAM and although it's going to require posibly an extra micro (with alot of outputs!) just to handel the memory refresh and timing it's still something I won't get over my head doing. http://www.sxlist.com/techref/mem/dram/slide2.html
Ask them for a sample. Companies will usually be willing to give away 2 or 3. (Just don't go around getting millions of free samples people, or companies will stop. )
The pitch on the TSOP is .8 mm that should be pretty easy to solder with a good soldering iron (at least adjustable, if not temp controlled) a fine point and some fine solder. The hardest part would be the adapter/etching your own board. As for the SIMMs look up the part number on the chips to make sure they are static ram, not dynamic ram. (not sure, bit before my time... barely) http://www.google.com/search?hl=en&rlz=1T4GGIH_enUS225US225&q=30+pin+SIMM&btnG=Search http://en.wikipedia.org/wiki/SIMM wikipedia has the pinout for a SIMMs right there.
All simms are dynamic ram I think and the ones I am probobly going to buy I have been studying the data sheets of hard. It looks perfectly posible to interface them with an 8bit micro running at 10mhz. I like the look of the chalenge dynamic rams have now I have studyied the data sheets and a few articals on dynamic ram. I built a circuit using a static ram (6116) last year and therfore to get a fealing of progresion I think moving onto a more complex memory type will be of benifit to me. btw in case people are wondering I am building a device that records an anolog input and plays it back at a reduced rate, I wanted to do all kinds of things involving pitch bends and such like but to do it in the digital domain with the equipment and maths knowlage I have as an A lvl student would be too expensive and not likley to be succesfull. So I have gone with designing my own PWM ADC and using 16F84pics to do the same thing with less sophistication (I have to change the time base to produce a pitch bend so it can't be done in real time - hence the need for some memory to encode a 200khz bit stream to!). I guess this is alot more advanced than is needed for an A lvl project but I am I think the best or second best based on exam scores electronics student in my year so I feel I have alot to live upto and I could bash out a simple project needed for the coursework requirment in an afternoon which would be dull.
update: I am using a 30pin simm and have succesfully done read/write/cas before ras refreshes on it using a PIC to controll the timing and refresh cycles. There not very nice to work with though as they greatly increase the complexity of a project, although they are very very fast if you use stuff like fast page mode. Overall only use if you rearly can't use a static ram. I adapted them to bread board by soldering right angled pins to the fingers and then just plugging the entire modual into a 30strip work area on a stange breadboard with no edge I found.
I have seen SMT breadboard adaptors in various stores. If you are in the US and have a Fry's near by, you may find one there for your part. But they usually are not terribly cheap that way ($7-12 and some are even higher). Anyone who deals in electronics for labs should carry these too. Off the top of my head, try looking at Jameco.com and Allelectronics.com as both cary various odds and ends.
