saturnus docs

About the HP calculators that saturnus runs in the browser: the models, their commands, how the Saturn processor inside them works, and how to move files between a computer and a real calculator.

Models

• HP 48SX
• HP 48GX
• HP 49G
• HP 38G
• HP 39G
• HP 40G
• HP 42S
• HP 27S
• HP 17BII
• HP 17B
• HP 28S
• HP 19BII

Each page tells the model's history, what makes it special and how saturnus runs it.

Command reference

Every command of the 12 models, with its stack effect, what it does and examples with their results from the emulated calculator. Search a model's commands by name or by what they do.

How the Saturn works

The hardware inside these calculators, for developers:

• The CPU
• Memory
• The display
• The keyboard
• Timers and interrupts
• The serial port and infrared

Moving files to a real calculator

For owners of a real HP calculator:

• Cables
• Kermit and XModem
• satx, the command-line tool
• Files in the app

For AI apps

Every page is also available as Markdown: /saturnus/docs/48gx/ as /saturnus/docs/48gx.md. llms.txt lists them.