VOTE: CPU for OTZ80 - eZ80 20 MHz or 50 MHz?

[alberthrocks]

UPDATE: This poll will end tonight. If you haven't already voted, please do so now! (8/9/2010 is the end date!)
UPDATE: Majority says eZ80 50 MHZ, underclockable to 20 MHZ! Voting is now closed. This is now a final feature in OTZ80!

[This is a separate topic to help keep things organized.]

What will the CPU be? It seems everybody has agreed to eZ80, so we'll use that.

What clock speed will we use?
There's only 2 choices here AFAIK (from http://digikey.com/PTM/PTMPartList.page?site=us&lang=en&ptm=6200&WT.z_ptm_structured=Buy%20Now%20Button): 20 mhz or 50 mhz?

So VOTE: eZ80 20 mhz or 50 mhz?
(Ignore the specs about memory for now. We'll decide on them in a later poll.)

[DJ Omnimaga]

20

Less power usage. The price difference is not great, but for the user, the long-term price difference will be, with all those batteries being wasted.

[calc84maniac]

edit: I gave a wrong link :O

[SirCmpwn]

Multithreading, guys.  It would be really nice, am I right?

[t0xic_kitt3n]

I say 20 mhz. Remember that eZ80 processors are about 4x as efficient as ordinary z80s, so its like having an 80 mhz z80.

[JonimusPrime]

Not to mention if we want to beat TI on the price point every $ saved will matter and make it more accessible to everyone.

[Mighty Moose]

20 mhz is already better than ti's 83's and 84's (albeit by only 5 mhz for the 84's).  If we're out there to beat ti, use 20.  50 is a little overkill.

[DJ Omnimaga]

Moved to Z80 hardware

Also, we have to take in account that TI may respond to us by dropping their prices to something much lower than us if we get popular. This will hurt our sales and force us to stop producing our calcs, allowing TI to re-increase their prices again in countries where there are no laws against monopolys.

[matthias1992]

20

Less power usage. The price difference is not great, but for the user, the long-term price difference will be, with all those batteries being wasted.

I can hardly call THAT wasted. With 50mhz we have the world! (okay a little dramatic but read on..it gets more dramatic )

why so conservative all? This is a very rare change we have! We want it to be durable right? so make it 50! We could do multitasking (drawing graphs whilst doing 1+1) and much more! The possibilities are far more unbound and the price difference is near nihil. We could easily underclock the calc later anyway and let the user choose betwen slow mode and fast mode. With rechargeable batteries batterties shouldn't be a problem.

We have until now pretty much copied TI, the design "must" be the same, we use the same sort of processors we add some ram. But oh no, no bigger screens please, no faster processors please. I mean really, this is a unique change! We could make the calculator far more then a calculator when choosing 50mhz! It adds to resale value and it costs about $5 more in production.

Will you let slip away yet another change to make this product great?!


I have been noticed that this comment might very well been seen as offending, if that is so then my apologies for its intends were not so. The above was just a act of desperation to get people voting for 50mhz. The "joke" about no bigger screens and no faster processor wasn't aimed at anyone specifically. it's intend was to help others "realize" that up till now 'we' haven't really done anything spectacular with the OTeZ80. This is just my opinion and above are the arguments for supporting it. If anyone felt jumped on by this then I, again, apologise. Just realize that it's intends were not to do so.

[calc84maniac]

20MHz is already over 5 times as fast as the TI-84+SE.

[alberthrocks]

It's not that we don't like fast - we do. But keep in mind that this product isn't designed for ourselves - it's for the students and educators. They don't care if it's 50 MHz or 20 MHz. They care about its look, its price, and its functionality.

20 MHz looks pretty good. It's already faster than TI's own calc, but MUCH faster with eZ80 itself.

[JonimusPrime]

Batteries are a huge issue, and multitasking is just dumb for a single purpose embedded device I hate to shoot you and SirCmpwn down but that's just the case. Even at 50Mhz the overhead is not worth it, period, and really as nice as the z80 and eZ80 series procs are I'd almost say we are being dumb for not using something without a FPU built in. An IEEE compliant FPU would make it shit easy to make a calculator that can do all the math we need it to.

[DJ Omnimaga]

Matthias1992, calm down, and Calc84maniac, isn't it more like 1.333x faster than the TI-84+SE? The TI-84+SE is 15 MHz.

EDIT: Jonimus, would it be as cheap, though?

[calc84maniac]

Matthias1992, calm down, and Calc84maniac, isn't it more like 1.333x faster than the TI-84+SE? The TI-84+SE is 15 MHz.

Nope, because instructions on eZ80 take less clock cycles than on Z80. It's generally a 1 to 4 ratio. So eZ80 at 20MHz has around the performance of a Z80 at 80MHz.

[DJ Omnimaga]

Aaah ok, thanks for the info.