u/Haunting-Hold8293

Hallo zusammen,

ich möchte ein Hobbyprojekt vorstellen, an dem ich arbeite.

Begin war die Frage, warum es zwar viele gute wissenschaftliche Taschenrechner gibt, aber kaum einen, der speziell auf die Anforderungen eines Informatikstudiums zugeschnitten ist. Also habe ich beschlossen, meinen eigenen zu entwickeln (ich besitze ua den TI-nspire den ich jedoch lieber meide).

Der Rechner läuft auf einem Raspberry Pi Pico mit kapazitivem Touchdisplay und ist vollständig Open Source.

Aktueller Funktionsumfang:

• Wissenschaftlicher Rechner
• Umschaltbare Präzision mit 40 / 80 / 128 Dezimalstellen
• Funktionsplotter
• Komplexe Zahlen
• Statistik
• Einheitenumrechnung
• Integrierter BASIC-Interpreter
• USB-Anbindung inklusive Windows-Anwendung
• Wahrheitstabellen
• DNF- und KNF-Erzeugung
• Boolesche Algebra
• Gatter-Simulator
• Neuer grafischer Circuit Mode mit Drag & Drop, Zoom und Live-Simulation
• Umrechnung zwischen Binär-, Hex-, Dezimal- und weiteren Zahlensystemen
• IEEE-754- und Bitmanipulationsfunktionen

Mein Ziel war nicht einfach ein weiterer Taschenrechner, sondern ein Werkzeug, mit dem man Zusammenhänge verstehen kann.

Beispielsweise lässt sich eine boolesche Funktion nicht nur berechnen, sondern Schritt für Schritt untersuchen:

>

Im neuen Circuit Mode können Gatter platziert, verbunden und live simuliert werden. Werden Ein- oder Ausgänge geändert, wird die komplette Schaltung sofort neu berechnet.

Als Nächstes sind unter anderem geplant:

• Weitere mathematische und informatische Werkzeuge

Der Rechner ist in erster Linie für mein eigenes Studium entstanden, da ich genau die Funktionen integrieren wollte, die mir beim Lernen gefehlt haben.

Der komplette Quellcode ist auf GitHub verfügbar:

https://github.com/rudolfstepan/pico-sbc/blob/main/docs/user-manual.md

Ich freue mich über Feedback, Ideen oder Anregungen. Besonders interessiert mich, welche Funktionen ihr euch auf einem wissenschaftlichen Rechner für Informatik und Mathematik wünschen würdet.

(Ich kann Fehler am Code nicht ausschließen und daher übernehme ich auch keine Verantwortung auf falsche Berechnungen.)

Over the last months I have been working on a 6502 SBC emulator, mainly as a development and testing environment for my own 65C02 single board computer experiments.

At some point the FPGA part became large enough that keeping it as just a folder inside the emulator repository no longer made sense. So I split it out into its own repository:

https://github.com/rudolfstepan/6502-sbc-fpga

The goal is not to build a C64 clone or to recreate one specific old machine. It is more of a clean, expandable 6502-based home computer architecture that can run real 6502 code, boot ROMs, BASIC demos and hardware experiments.

Current features include:

• 6502-compatible system architecture
• FPGA video output
• text mode with character rendering
• 16-color output
• bitmap graphics experiments
• PS/2 keyboard support as a practical input solution
• UART-based development and debugging
• a custom memory-mapped sound chip
• BASIC demos running directly on the FPGA system
• board support work for multiple FPGA boards, currently including PIX16 and Tang Primer 20K

One important design goal is that the FPGA implementation stays close enough to the emulator that ROMs and test programs can be developed and debugged in the emulator first, then moved to real FPGA hardware with minimal changes. For me this is the most practical workflow, because it avoids constantly flashing and testing blindly on hardware.

The project now also has its own Wiki, because the amount of documentation, board-specific notes, memory maps, build instructions and hardware details outgrew a single README.

What I find most interesting is the evolution of the project. It did not start as a complete computer. First I tested a small working 6502 system, then video, then keyboard input, then color, then bitmap experiments, then sound. Each feature had to work as a small proof of concept before scaling it further. Moreover the FPGA Project startet on a Spartan6 Board with VGA output. Than I tried to add a 2nd Board, Sipeed Tang Primer 20k which brought me to some refactoring to make the solution more or less board independent. I moved and capsulated code into closed core modules to bring up a generic folder structure.

I will not hide that also used AI tools quite heavily during development, especially for documentation, scripts, refactoring support and repetitive HDL or tooling work without such a heavy project would not be able and live. More important is understanding the architecture, the bus timing, the memory map, the constraints and what the system is actually supposed to do. Let me make that clear, as a professional solution architect AI is very powerful when used as an engineering assistant, but it does not replace knowing what you are building.

So the next steps are proper load/save support without depending on the PC UART (eg a second SDCard reader implementation as a trivial peripheral drive), better storage integration, more complete board support and further cleanup of the hardware abstraction between boards.

It is still experimental, but it has reached the point where it feels less like a demo and more like a small custom home computer platform.

You are pleased to look at the screenshots, made by cam and also by HDMI grabbing.

The newer 2025 model is better in everything in comparison to the 2024 model so far.

Bigger screen size. The 11" fits an eu din a4 page better than the 10.2".

The newer frontlight technique looks a page more paper-like with less glossy parts.

The performance has been much improved for paging or zooming which feels lees e-ink and more LCD.

Handwriting is more paper-like because you feel scratching on the screen with the pen which is a better haptic feedback during writing. In comparison to the remarkable2 which I owned previously the 2025 model is close to that.

Honestly the 2024 model would be great and enough as a ebooks reader with annotation support but not as a working pad for writing math by hand.

Another thing I've mentioned is that only the 2025 model has the capability to export notes to Google or Microsoft cloudspace even both kindles run with the same firmware.

I know that there lot of yt videos for comparison but I want to share my first impressions.