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39 lines
1.7 KiB
Markdown
39 lines
1.7 KiB
Markdown
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# TI-83+/TI-84+
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Texas Instruments is well known for its calculators. Among those, two models
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are particularly interesting to us because they have a z80 CPU: the TI-83+ and
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TI-84+ (the "+" is important).
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They lack accessible I/O ports, but they have plenty of flash and RAM. Collapse
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OS runs on it (see `recipes/ti84`).
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I haven't opened one up yet, but apparently, they have limited scavenging value
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because its z80 CPU is packaged in a TI-specific chip. Due to its sturdy design,
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and its ample RAM and flash, we could imagine it becoming a valuable piece of
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equipment if found intact.
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The best pre-collapse ressource about it is
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[WikiTI](http://wikiti.brandonw.net/index.php).
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## Getting software on it
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Getting software to run on it is a bit tricky because it needs to be signed
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with TI-issued private keys. Those keys have long been found and are included
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in `recipes/ti84`. With the help of the
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[mktiupgrade](https://github.com/KnightOS/mktiupgrade), an upgrade file can be
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prepared and then sent through the USB port with the help of
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[tilp](http://lpg.ticalc.org/prj_tilp/).
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That, however, requires a modern computing environment. As of now, there is no
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way of installing Collapse OS on a TI-8X+ calculator from another Collapse OS
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system.
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Because it is not on the roadmap to implement complex cryptography in Collapse
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OS, the plan is to build a series of pre-signed bootloader images. The
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bootloader would then receive data through either the Link jack or the USB port
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and write that to flash (I haven't verified that yet, but I hope that data
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written to flash this way isn't verified cryptographically by the calculator).
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As modern computing fades away, those pre-signed binaries would become opaque,
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but at least, would allow bootstrapping from post-modern computers.
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