Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Messages - floris497

Pages: 1 2 [3] 4 5 ... 15
Other Calc-Related Projects and Ideas / Re: 3D nSpire Dock
« on: October 13, 2013, 05:49:39 am »
In transistor logic, no, it wouldn't be. The low is determined by how low the transistors can pull (usually 0.5v to 0.7v) and is not affected by much else as far as circuits go. This limit is determined by the method by which the transistors function, and their materials. (Germanium diodes can pull down to 0.2v, for example, but they're very slow). This value is actually equivalent to the voltage drop across the diode. This means a 100 mv difference would put the "high" value at about 0.8v for standard circuits.

The high side is more arbitrary, but if you go too low (read: <1.7-ish volts for high-end consumer electronics) the circuits become unstable, reporting 0 where it should be 1, and vice versa. They push it as low as they can for speed and power reasons, as you said, but 100 mV difference is less than the thermal fluctuation, even ignoring problems like crosstalk.

My biggest reason doubt this, though, is that the CPU operates at 3.3v. 3.3v USB, while not spec, would make sense, as they would have voltage-adjusting circuitry off-board. (see the RS232 port for an example of exactly this design choice in use) Choosing to lower the voltage any more than the CPU is running, simply for I/O purposes, and taking the protocol even more out of spec? Why? It won't be faster or more efficient, thanks to conversion inefficiencies.

The nspire is not a fancy, cutting-edge piece of electronics. As far as mobile ARM devices go, it's quite ordinary, and an old ordinary device at that. I just don't see TI using such futuristic technology in a device like this.

oke, thanks for explaining, i'm going to built a little regulator like that soon, not sure why they have coils? L01B L02B what are those for? is that for cleaning the signal? can i leave them out of the circuit?

Other Calc-Related Projects and Ideas / Re: 3D nSpire Dock
« on: October 13, 2013, 04:59:30 am »
Yes, it would be odd to have 100 mV USB. From what I can tell from looking at the insides, there is no difference from the USB on the dock and the USB on the top of the calculator, other than the dock is missing some of the protection circuit. They are separate on the inside of the calculator, so it's not the same port as the normal one.

I'm surprised there is 100 mV anything since the lowest I've ever heard ttl "high" voltages being is still above 1V. A 100mV signal would be considered "low" by most logic circuits. This would mean they are intentionally decreasing the signal voltage out of the CPU with amplifiers, which doesn't seem to be the case.

100 mV is INSANELY low for transistor logic.

maybe i heard that wrong somewhere, can it bet the difference between high and low? 5V change in voltage takes a lot of time, where time is speed/energy?

Other Calc-Related Projects and Ideas / Re: 3D nSpire Dock
« on: October 09, 2013, 04:17:55 pm »
I could finally identify the 2nd USB port pins on the TI-Nspire J01/Dock connector:
pin 21: USB Data+
pin 20: USB Data-

But it seems that we'll need to put some more electronic on those pins before it works:

Source with more information: (in french for now)

that means i can go and work on the circuts for the dock.

That would be most likely a voltage regulator (5v to 3.3v TTL). Well that's what I assume at least.

usb should be 100mV for the data cables, so not sure? (hope i'm correct at this one)

Miscellaneous / Re: Random YouTube Videos
« on: September 14, 2013, 04:07:22 pm »
I have a mighty want for this:

this is a cool product want to see it in action promising thing, not sure if i want it.

Other Calc-Related Projects and Ideas / Re: 3D nSpire Dock
« on: September 12, 2013, 03:08:23 pm »
I am wondering what you are going to use for the dock connector? I can't seem to find anything that has the right pitch.

how do you mean like how to connect it? what kind of connector?

i also cant find any connection of usb over the dock @ 19,20,21. someone told me the rx tx are 100mV so not 5 and if i don't connect the power it might work. but the nspire software didn't recognise the calc :( (maybe i already broke it..)

Miscellaneous / Re: Random YouTube Videos
« on: September 10, 2013, 12:10:49 pm »
this is kind of a cool song (read lyrics if not very good at english :p)

Other Calc-Related Projects and Ideas / Re: 3D nSpire Dock
« on: September 10, 2013, 07:31:03 am »
Well thats a really hard question, I think the have no idea what they start.

if people are able to make good guns with 3D printers that can mean the end of 3D printing in a lot of countries :(

Other Calc-Related Projects and Ideas / Re: 3D nSpire Dock
« on: September 09, 2013, 04:33:31 am »
They both do have the slide case track thing going down the side in the same place, so the bottom connectors are compatible.
Also you can get a Makerbot for a little over $2000, which is more affordable. Or, of course, you can have a local place like your school print it for you on one of their printers.

not sure if i can use those facilities on my new school but now i can also make pcb's at school.
And i can tell you i have no spare $2000 on my bank :p

but if the connectors are compatible in the same slide i'm sure to make them both fit, of i'll make a little switchable part for it.

News / Re: New TI-Nspire CX hardware revision K
« on: September 08, 2013, 05:08:31 am »
Looking trough the pictures That the new boards contain the RU logo

does that mean something?

Other Calc-Related Projects and Ideas / Re: 3D nSpire Dock
« on: September 08, 2013, 04:55:43 am »
something i found on kickstarter:
also, their website says $3299 which is actually affordable for private households O.O (
The quality is really high and the price/quality is really low on this one, but still  more money than i have laying around.

Is it true that the bottom part of the cx and non cx are the same? than this might work for both.

think it's fun to use only TI chips in this one :p

Other Calc-Related Projects and Ideas / Re: 3D nSpire Dock
« on: September 07, 2013, 12:58:40 pm »
I'm going to finish this thing, now we know a little more about the dock and where the usb is, i'm going to design some electronics to get support for: USB, UART, Charging and header pins for all the pins from the dock. is there anything else that should be implemented? a specific kind of chip? or if you have other suggestions. tell me

TI-Nspire / Re: nspire Linux Questions
« on: August 28, 2013, 04:54:54 am »
Thank you, I will test it as soon as i find my My usb cable in my room of endless useless and useful stuff :p

TI-Nspire / Re: nspire Linux Questions
« on: August 27, 2013, 04:29:57 pm »
the Arduino wil reboot with every new contact that is made with it

And Thanks :)

TI-Nspire / Re: nspire Linux Questions
« on: August 27, 2013, 04:23:34 pm »
my current version does not have screen. you can communicate with the arduino with screen, if you use cat or echo to the arduino it will reboot, as far as i know screen keeps contact all the time

TI-Nspire / Re: nspire Linux Questions
« on: August 27, 2013, 04:20:18 pm »
I have no idea how to compile my own version.. can someone compile a kernel with support for 'screen'? to interact with my arduino.

or teach me how to do it myself.


Pages: 1 2 [3] 4 5 ... 15