FAQ

They are regular .ti59, .ti58, or .ti58c text files that can be anywhere on the file system. On Mac, Windows and Linux, Preset opens them from disk (on Windows and Linux, Settings › Files sets the folder it starts in); on iPhone and iPad, use the built-in file picker.

Yes. The GitHub repository includes an 'examples' folder with a selection of .ti59, .ti58, and .ti58c files, and the 'TI-59 Software Collection' page has downloadable copies. There's also a step-by-step tutorial that builds one from scratch.

This feature is still a bit experimental. You can load these examples in the ASM OVERLAY box under the debugger's CPU tab: Select File, then Run. Clear removes the overlay again.

On Mac, iPhone and iPad they are stored in the app's iCloud storage (or the app's local folder when iCloud is off); use the Crd buttons to load or save them. On Mac, they are also in Finder under 'iCloud Drive/Calc-U-59'. On Windows and Linux they are in the Calc-U-59 folder in your home folder, unless Settings › Files names another.

The TI-58C state file (ti58c.mem) is stored next to the cards: in the app's iCloud storage on Mac, iPhone and iPad, in the card folder on Windows and Linux. Unlike a preset, which you load on demand, this file is the TI-58C's persistent state — it's written and loaded automatically whenever you switch to the TI-58C model, standing in for the battery-backed static RAM the real hardware used to keep memory alive between sessions.

Yes. Use the debug pane: CALCULATOR for program state and registers, CPU for the ROM instruction trace, and LOG for text output plus trace controls.

Open the debug pane, switch to LOG, and turn TRACE on. The app writes a binary session file (CALCU59_TRACE.bin; CALCU58_TRACE.bin or CALCU58C_TRACE.bin for the smaller models) to the trace location: on Mac the one set in Settings (local by default), on iPhone and iPad the app's iCloud folder, on Windows and Linux the trace folder from Settings › Files. If the file can't be created or reaches its size limit, the app tells you.

You first need the trace file on a computer. On Mac, Windows and Linux it already is. An iPad or iPhone writes it to the app's iCloud folder, so it syncs to iCloud Drive; retrieve it from there on your computer. Download the 'read_trace.py' script from GitHub to convert the binary file to a readable format. The script is available in the 'tools' directory of the GitHub repository.

The CPU tab only traces while it is visible. When you switch to it, the heat map resets because any activity since you last left would be missing anyway. Exception: if the CPU is already frozen when you switch, the heat map is left intact — there is nothing new to miss.

In the CPU tab, FREEZE ON START (F.START when the panel is narrow) arms a scan-loop exit trigger: it freezes the moment the calculator leaves the keyboard idle loop — either because you pressed a key (the ROM exits the loop to handle the keystroke) or because the calculator was reset. This lets you catch the very first ROM opcode of a key-press handler without having to time a manual FREEZE. Only one FREEZE ON START can be armed at a time; arming one tab silently disarms the other.

Switch to the CPU tab and press FREEZE ON START. Then go to the calculator and press Reset — the CPU will freeze at the first ROM instruction of the reset routine. Use STEP to walk through it one opcode at a time.

This is expected. The ROM's key-debouncing logic registers a keypress only for a very short window. When the freeze fires, the CPU freezes at the first instruction after the scan loop exits — but that window has already passed by the time you press RESUME or STEP. The key handler never sees the keypress and the calculator returns to idle. Use a TRACE capture instead: it records the full keystroke sequence without stopping the emulator, so the debounce window is never interrupted.

Yes. Copy or cut the output, and paste it into a text editor.

Add a CUECARD: section to a preset: set Template to MagnetCard or CueCard, then fill in fields A through E and A′ through E′ for the two key rows. Load that file (or write it onto a virtual magnetic card to keep the label with the card) and it appears on screen. See Loading a preset → Labeling the A–E and A′–E′ keys for the format, the math shortcuts, and the loading options.

Almost always a hidden .txt extension. Some text editors, and Finder/Explorer with extensions hidden, save my-preset.ti59 as my-preset.ti59.txt without showing it — the file looks right in the file browser, but the preset picker only accepts .ti59, .ti58 and .ti58c, so it's shown grayed out and can't be selected. Turn on "Show file extensions" (Explorer) or "Show all filename extensions" (Finder), or rename the file from a terminal, and it should load normally. See the preset tutorial for more on avoiding this.