Hello all!
I'd like to like my Ti-84 (or other model) calculator to my Raspberry Pi's console as a display and input method that I'd have in my backpack most of the time anyway. The shell is powerful enough to make the calculator amazingly useful, with applications such as elinks enabling simple full web browsing capabilities, etc. Software would need to be written for the Pi (most likely a Python script, since that seems to be the standard) for sending the contents of the shell to the Ti and receiving input back, and a program on the Ti to display the console and send input back to the Pi. Preferably, communication could take place directly over USB with no intermediary layer between the Pi and the Ti, for keeping hardware costs to a minimum and to make it easy to set up for everyone with a Pi and Ti calculator!

Enjoy this food for thought. If you can help out with documentation on how the protocol of the Pi's USB, I see that being one of the hardest elements here.

-- williamtdr

BrandonW's Linky for the 89T makes it possible to expose a 89T as (one at a time, among others):
* a PL2303 USB serial adapter with a simple, if fairly slow, serial console. I've tested it on my own 89T against CuteCom.
* a HID keyboard (I filled the keyboard mapping code in BrandonW's framework);
* a HID mouse.
The 84+/84+SE/84 Pocket and 89T use the same USB controller, so the 84+/84+SE/84 Pocket could certainly provide the same functionality, with some effort.

A 96x64 screen is ludicrously small for elinks, though... Even the 320x240 screens of the 84+CSE / Nspire / Prime are fairly ill-suited to elinks.

Lionel,
Great to know someone has done it before. Would this be possible without a USB to serial adapter? The 84 has a standard mini USB port.

There's no USB to serial adapter involved in Linky usage
The 89T directly acts like a serial adapter device, HID keyboard, HID mouse.

Thanks to the host mode capability of the USB controller (required for calculator-to-calculator transfers), the B/W 84+ family and 89T can even do more complicated stuff, such as PS3JB and PS3JB89.

Makes sense. So where's a good place to start here?

I was just thinking last night about how it would be cool if someone made a serial terminal emulator using the link port, KermM has already written a serial library for the GPS project.

You might want to take a look at this: http://www.ticalc.org/archives/files/fileinfo/256/25604.html

So, downloaded telnet83+ and ran it successfully on my 84+, then hooked the tx serial pin on my raspi up to the rx pin on my 84+'s serial port. But all that happened when I booted the pi was the blinking cursor occasionally stopped blinking. Any ideas?

That program is designed for the greylink cable, which converts DBUS signals to RS232 serial. Once Kerm releases his serial library, I might be able to modify telnet83+ so it can be used without the greylink, the only thing that would be necessary would be a logic lever converter, because the calculator operates at 5 volts while the Pi uses 3.3.

Yup, was thinking a simple resistor to solve the problem for now, see if the 3.3v is enough to activate the 5v on the 84 (I suspect it would be). Is there a link somewhere on how I can make a greylink cable, and would it be compatible with the Pi?

You might want to take a look at this: http://merthsoft.com/linkguide/

Would this work? http://education.ti.com/en/us/products/computer_software/connectivity-software/ti-connectivity-kit/features/features-summary

Also, still confused as to how this is better than the plain old USB cable from the pi to the calc, simple as that is.

The USB on the 84+ is pretty complicated. Only a few people understand it (I think only BrandonW and DrDnar (but maybe more)).

No, because the greylink converts it to serial, but the usb one does something different

Ah. So I need to make something to convert from the 3 pins on the 2.5mm jack on the calc, then convert that to serial, then convert that serial to usb, then can I send info from the pi to the calc without any new software?

The canonical low-cost greylink alternative is the PIC link.

And it's fully compatible with the greylink?

Where can I download linky?

Your favorite search engine should be your friend here, it should point you to BrandonW's site