No EEPROM on the Propeller? Why not?

JoeCreate

I'm curious as to what some of the reasons were·for why·you didn't include an EEPROM on the Propeller (embedded)?· Considering in most every case the Prop needs to load it's program from an EEPRROM if you want it to work stand-alone.·

I do see the flexibility of having it external as well, so I'm not saying it SHOULD be internal, but I just though it would also be nice not having to add the external components (EEPROM+PullUps).··· The Prop could check for an external eeprom as it does now to maintain the ability to load from external sources, but then check it's internal eeprom·(on the same i2c bus, but with internal pullups and a·different EEPROM·Address)·if no external was found.

Or...
"I think the Propeller should have an integrated EEPROM for program storage to eliminate the need for the additional external component."
Why Not?
... just to fuel the conversation
·

deSilva

There are different processes to create a silicon structure. I am not expert enough to give you a detailed explanation. (Sorry to disappoint my fans ..)

However the process Parallax uses is fine for high speed LOGIC, ROM and RAM, but not for the specific EEPROM cells.

There is a similar situation with FPGAs

The solution would be a "hybrid" adding a Prop and a Flash die on one chip. Have a look at the ETRAX100 controller posted somewhere here, which also integrates 16 MB (!) dynamic RAM with this technique.

But it is not exactly low cost....

Parallax issued the PropStamp instead. (Which is not exactly low cost either )

Fred Hawkins

Maybe it's cheaper to surface mount them both and then pot them up.

parts-man73

Fred Hawkins said...
Maybe it's cheaper to surface mount them both and then pot them up.

Sounds like a Prop-stick USB. (Which also contains a built in prop-plug)

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Brian

uController.com - home of SpinStudio

Timothy D. Swieter

deSilva is correct in that the reason the Prop does not have a built in EEPROM is because of the process used for making this particular chips. There are many processes for building chips and there are tradeoffs in cost, time, design constraints.

If size and space are a concern, the QFN package for the Prop and the a small surface mount package for the EEPROM don't take up much room.

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Timothy D. Swieter
tdswieter.com

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One little spark of imagination is all it takes for an idea to explode

JoeCreate

It's not really a space issue, more of a convenience thing. But to keep costs down and keep the chip cheap, I don't mind adding it externally. It's interesting to learn a bit about the different processes required to make the different types. I'm a Fab-Dummy, never been involved in a fabrication process to know there are different methods specific to the different types of chip. Always willing to learn though. Thanks.

Timothy D. Swieter

There is an entire world of science to the process of semiconductor materials and processes. I took one tiny class on it during my undergrad and it was enough for me to realize that I know enough to know I don't know enough. It is very interesting to hear someone talk about the science if they are able to keep it simple. You could try a text book on the subject but it would be like taking a sip from Niagra Falls unless you are very good with electronic theory.

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Timothy D. Swieter
tdswieter.com

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One little spark of imagination is all it takes for an idea to explode

rjo_

longevity...

everything evolves, if the eeprom was on the chip, it would be a fixture. By placing it off chip, you allow for progress.

I hope I'm not to going too far off-thread here, but I was trying to read the specs on the eeprom and it appears that with the same pin count you can talk to a series of eeproms.

I wonder what the timing differences are for all of the various options for non-volatile memory?

Rich

deSilva

It was interesting to me that obviously none of you has a PropStamp and most of you even do not seem to know that this exists in the first place .... So it most likely was a "flop", though it had deserved a better fortune. But maybe 16 I/Os are too little and $68 ist the wrong price tag

I have two BTW; I managed to fry one, but it suits well as a piece of "show and tell", and a second working one if people get really interested

JoeCreate

I thought the PropStamp was too pricey. The footprint is nice, but I haven't been space-restricted, yet. The proto board is perfect. Either way, the eeprom is still an external component on the PropStamp as well. Even the Basic Stamps ara a Board full of components, not just ONE chip.

I'm not saying it's Bad being off-chip, and if I go over all the reasons in My head (nothing to do with fabrication), I'd probably leave it off-chip as well. I was just curious as to Why Parallax decided Not to put in on-chip, or if it was never even a consideration (due to fabrication).

I think I liken it to my trusty PIC16F690. Just add a 3v battery, a resistor, and an IR LED and I have an Infrared Beacon for my robot to navigate with. But, that's what PIC's are good for in my case, small, dedicated tasks, both On and Off the Bot. The Prop would be overkill for this. The Prop is for bigger and better things, so adding a crystal and eeprom and two resistors is not a big deal. The PIC works great as an Analog to Digital converter to i2c interface for about $1.40US. But the Prop is the Boss.