Multiplexed eeprom
- Thread starter beny1949
- Start date
If these are the type of I2C Eeproms which have an A2-A1-A0 address, you can wire all A2's and A1's to 0V and then connect all A0's to something which asserts only one line at a time, ( eg, a 4-to-16 line decoder ). All Eeproms will then be on the same address, and you'll have to select which one you actually want to communicate with through the selector/decoder.
The A2 and A1 can be connected to decoders as well, giving even greater capacity.
Two 3-to-8 decoders would allow 64 Eeproms, two 4-to-16 would allow 256 and three 4-to-16 would allow 4096. Using 24LC1025's, that would give access to 512MB of storage, and you can go further still
Edited by - hippy on 10/03/2007 18:23:32
The A2 and A1 can be connected to decoders as well, giving even greater capacity.
Two 3-to-8 decoders would allow 64 Eeproms, two 4-to-16 would allow 256 and three 4-to-16 would allow 4096. Using 24LC1025's, that would give access to 512MB of storage, and you can go further still
Edited by - hippy on 10/03/2007 18:23:32
An interesting project, but 64 x 512Kbit EEPROM = 4Mbyte = >> £120 . Plus fairly hefty pcb size. With data taking about 3 years to download.
SD a fiver plus interface for 256Mb. Half the size of a fag packet. £30 all in? Directly readable by PC in a twinkle of the eye. Archiveable media.
It'll impress your next door neighbour without a doubt , but where's the sense?
SD a fiver plus interface for 256Mb. Half the size of a fag packet. £30 all in? Directly readable by PC in a twinkle of the eye. Archiveable media.
It'll impress your next door neighbour without a doubt , but where's the sense?
They're pretty impractical when you talk about using 64 of them, but 128kb of storage is a LOT for most projects. Especially when microchip.com is willing to let you sample both the 24lc1025 and 24fc1025 (which might get a slight gain from overclocking), at 3 a piece, for free! I'm going to add one of those 24FC1025's to my little laptop project, as it will make a nice addition.
demonicpicaxeguy
Senior Member
http://www.microel-elisra.com/memory.html#StandardFlashEEpromProducts
forget the little microchip storage eeproms try one of these
most of the data sheets are only 22 pages long and they are fairly simple to interface to (aparently) but you'll need a 40x to use some of them
but we're talking up to 2gbit of storage
forget the little microchip storage eeproms try one of these
most of the data sheets are only 22 pages long and they are fairly simple to interface to (aparently) but you'll need a 40x to use some of them
but we're talking up to 2gbit of storage
Yeah, if it's not a 2-wire interface, and if it's any finer pitch than SOIC (and then it better be awesome!), it's way too much of a hassle. Most things that a picaxe can be used for don't require several MB, just because it would take too long to process in any sort of way, but a few hundred KB can open up some better datalogging applications. If you're using something that needs a 40X to use, you might as well just use one of those serial-to-SD card things.