I think the idea was to build two, one arm, one z80, for both product lines.

ARM Cpus will almost always be better than x86 CPUs power-wise. An energy-effecient x86 CPU compared to a rather poor ARM will measure about equally. x86 focuses on backwards compatibility, so it's software is compatible across models. This also makes it very complicated and inefficient. ARM is one of the best (if not the best) CPUs for portable devices. Ultra-low power x86s are just really really weak, particularly efficient (for x86) CPUs. We can get a much more powerful ARM for less cost.

If we do use an accelerometer, can we at least use a Tuning Fork gyroscope with it? (They're in the Wii motion Plus) An accelerometer by itself is much more innacurate, and it shouldn't cost too much more.

Why not use a USB OTG port? They're very common, and fit both mini-A and mini-B cables, mini-A being for acting as a storage device, and B for acting as a host. They;re on the 84+, btw, as well as the 89T and nspire.

Well, we need to do something that seems secure. The fact is, an 83+ can run a CAS, but that didn't stop people from using it on the ACT. They just want it in the mindsets of students that the use of it shouldn't be available, not that it can't be done.

Edit: The password thing wouldn't be for OSes. It would be integrated into the default OS, like that nspire mode with the LED. I don't see that limiting other software, just that for the ACT/SAT you need to have the right OS on there.

Well, if we design first,  (which will take a really long time) and build later, then money issues can be resolved when we are more capable money-wise.

I think the calcs should have ACT/SAT modes, that the proctor can enter a password in the calc, and tell everyone after the test. (same pass for everyone, maybe wifi-based?) this would disable the features the teacher set (ACT no algebra, SAT has algebra allowed), and disables everything, except for wifi communication to the teacher's program only.

Depending on the spread of this calc, how many we plan to sell and such, that will determine how much customization we will do, IC-wise. At least 10,000 for any custom ICs, anything less will cost us too much.

Any ideas on what it will look like/be shaped like? What about a more effecient keyboard layout? The original QWERTY keyboard was actually designed to slow down first-time typers . Maybe we could design our own, based on the most-used keys. That would still be allowed on the ACT and SAT, and it would be better than a plain ABCDE layout.

@alberth That looks like something more beagle-boardish. Looks good, but It'll be a little too fancy for the z80 one.

Beagleboard isn't a great choice for making products. It's not the right shape (i'm assuming rectangular, or are we going 92-esque?) and it's kind of pricey. If we actually plan to sell these then we'll want to make our own board.

Maybe we could design a PCB that works for both models, then populate them differently for ARM and z80. That would save some money, but we'd need to find z80 and arm processors that are the same size :p

4 bit means 2^4 colors, or 16 colors. It was a standard for old computers, and viruses for windows sometimes force it into 4-bit color.

Color will really depend on the screen you choose, and the addressing capabilities of the processor to control it. high color depth on a low-res screen isn't hard for the processor, providing the screen does all the work (think like the nspire, with 16-level greyscale)

Color will be a design worry, not a programming worry, and not necessarily something we need to worry about yet.

yay! more nspire games! I always loved the block-dude puzzles. Some of them took me >30 tries, and I never reached the end.

Nothing went wrong, but they had a lot of trouble along the way.

They are building them steadily right now, at around 100 per week (i think)

I'm just saying we avoid some of the troubles they hit along the way.

Edit: for instance, they had many troubles with lack of communication with the chinese company for the cases, and there were many issues with the shipping companies, warped boards and >1000 qty shipments left in parking lots 3 blocks from the actual delivery location, to list a few.