collapseos/doc/ti8x.md
2019-12-02 13:51:36 -05:00

1.7 KiB

TI-83+/TI-84+

Texas Instruments is well known for its calculators. Among those, two models are particularly interesting to us because they have a z80 CPU: the TI-83+ and TI-84+ (the "+" is important).

They lack accessible I/O ports, but they have plenty of flash and RAM. Collapse OS runs on it (see recipes/ti84).

I haven't opened one up yet, but apparently, they have limited scavenging value because its z80 CPU is packaged in a TI-specific chip. Due to its sturdy design, and its ample RAM and flash, we could imagine it becoming a valuable piece of equipment if found intact.

The best pre-collapse ressource about it is WikiTI.

Getting software on it

Getting software to run on it is a bit tricky because it needs to be signed with TI-issued private keys. Those keys have long been found and are included in recipes/ti84. With the help of the mktiupgrade, an upgrade file can be prepared and then sent through the USB port with the help of tilp.

That, however, requires a modern computing environment. As of now, there is no way of installing Collapse OS on a TI-8X+ calculator from another Collapse OS system.

Because it is not on the roadmap to implement complex cryptography in Collapse OS, the plan is to build a series of pre-signed bootloader images. The bootloader would then receive data through either the Link jack or the USB port and write that to flash (I haven't verified that yet, but I hope that data written to flash this way isn't verified cryptographically by the calculator).

As modern computing fades away, those pre-signed binaries would become opaque, but at least, would allow bootstrapping from post-modern computers.