CMWOLF@mtus5.cts.mtu.edu (03/10/91)
I've been reading the Digest for about a month, and I've noticed that a lot of people on here know quite a bit about electronics. (As could be expected.) I would like to ask for some help with Dynamic Memory from anyone who has (extensive) knowledge about it. More specifically, I need to figure out how Dynamic memory works, and where I can find a good dynamic controller to handle all the refreshes and everything, so that I can treat it like static to my 'project'. If anyone can help me with this (major help) please contact me. Thanks! Christopher Wolf Electrical Engineer, Michigan Tech University
alans@hp-ptp.hp.com (Alan Sanderson) (03/15/91)
Christopher Wolf asks for information regarding dynamic RAM.
I have a few suggestions:
1. If you have a choice, and modest memory requirements,
use static RAM. It is very simple to use.
2. If you have a large memory requirement, dynamic RAM is
much less expensive, but does require some additional
interface circuitry. Most newer parts can operate in
a mode which provides "automatic refresh" - in which
you provide a CAS before RAS sequence, and the part
keeps track of its own refresh address.
3. Get the memory data book from the part manufacturer.
It will provide timing specifications, sample circuits,
and application suggestions. Many parts from different
vendors are interchangeable. Possible sources:
NEC, Hitachi, Samsung, Advanced Micro Devices (AMD),
Texas Instruments (TI).
4. If you are using a microprocessor, it will normally have
a way to generate a refresh signal. Look at its timing
diagrams. Check out the schematics of a PC clone or
similar piece of equipment. For DRAM, you will have
to demultiplex the row and column addresses for the
memory at appropriate times. DRAM controllers are
available, but are not necessary if you can generate
the appropriate signals with a few gates and flip-flops,
or a PAL (if you have a method to program it).
Have fun with your project. You should learn a lot
from the attempt.
Alan Sanderson Hewlett-Packard AMSO alans@hpams0a.HP.COM
US Snail: 1266 Kifer Rd. MS101S MaBell: 408-746-5714
Sunnyvale, CA 94086 FAX: 408-746-5890
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