Memory

Gaudware

I was wanting to know if anyone could tell me how to address multiple eeproms with out using a large amount of i/o lines and without using an i/o expander.
I appreciate any and all feed-back that is provided.

simonl

You can attach multiple EEPROMs on the same lines as used by the existing one. You set each one's address by appropriately connecting it's pins.

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Cheers,
Simon

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www.norfolkhelicopterclub.com

You'll always have as many take-offs as landings, the trick is to be sure you can take-off again
BTW: I type as I'm thinking, so please don't take any offence at my writing style

Gaudware

I understand what you talking about but I hook them in series, but I unsure how to set up and write to specific addresses with eeproms in a series configuration.
Thanks for you quick response.

Mike Green

As Simon indicated, each EEPROM has several pins that set the address range that the EEPROM will respond to. If, by "serial" you mean that you've connected all the SDA lines together and all the SCL lines together and you've set the address lines to all be different combinations, then the EEPROMs will appear to be a single block of storage. For example, if you have 8 x 24LC512 EEPROMs (each 64K bytes) connected this way, they will appear to the Propeller as a single block of 512K bytes.

Gaudware

Okay I understand it works like this:

(x)eeprom+(Y)eeprom=(x+y)eeprom

an eeprom of (x) size wired in series with and eeprom of (Y) size will create the same thing as a single eeprom of combined (x) and (y) size

Thanks for answering my question.

Here is a quick question if you guys don't mind.
Is their a limit the that amount of eeproms that you can have in series?

hippy

Is their a limit the that amount of eeproms that you can have in series?

Ultimately there probably is electrically although that number can likely increase if the I2C operating speed is reduced and the bus interface designed to suit.

The biggest limitation is in addressing the separate Eeproms in series which more likely than not renders any electrical issues moot. With three Eeprom address lines on the chips (A2,A1,A0) you can have eight Eeproms in series. Using more I/O lines and some clever address connections you can push that higher.

StefanL38

Yes,

this depends on the number of adress-pins
usually are three adresspins which is 2^3 = 8 adresses

You can see this in the datasheet of the eeprom

There are some more possabilities with different BASE-adresses of the chips
if you want to use that you have to control the adress in your spin-code
But i don't know anything about the details

I think it will be easier to use one BIG EEPROM instead of 1-16 smaller ones

or if you are thinking about more than 512kB to switch over to an SD-card which could be up to 2GB big

best regards

Stefan

Gaudware

Thank you guys for all your support.