u/HomeComp1977

I've bundled together some key extensions into a single download package together with the main emulator. This package represents the type of product a real company may have released around the April 1979 period.

The bundle includes:

* Core HC-77B Single Board Computer Emulator (1MHZ 6502)
* 3K RAM Expansion (4K Total)
* CRT Display Expansion
* ASCII Keyboard Expansion
* 8K BASIC Interpreter on ROM (load from address $D000)

This represents a complete usable late-70's home micro setup. Similar to real system boards available at the time at an affordable sub-£200 price point. (NASCOM, UK101, Microtan 65, etc).

[https://github.com/tmcd35/HomeComp/tree/master/releases\](https://github.com/tmcd35/HomeComp/tree/master/releases)

I've bundled together some key extensions into a single download package together with the main emulator. This package represents the type of product a real company may have released around the April 1979 period.

The bundle includes:

• Core HC-77B Single Board Computer Emulator (1MHZ 6502)
• 3K RAM Expansion (4K Total)
• CRT Display Expansion
• ASCII Keyboard Expansion
• 8K BASIC Interpreter on ROM (load from address $D000)

This represents a complete usable late-70's home micro setup. Similar to real system boards available at the time at an affordable sub-£200 price point. (NASCOM, UK101, Microtan 65, etc).

https://github.com/tmcd35/HomeComp/tree/master/releases

Emulating the DCT3 generation of Nokia phones — the MAD2 chipset that powered the 3310, 3410, 5210 and friends. As far as I know nobody’s done a full-boot emulator for these before, so most of it had to be worked out from firmware disassembly and old scene documentation from the 2000s modding community (NokiX era — I was part of that scene as a teenager (screen name spaceimpact33), which is where the domain knowledge comes from).
There are two tracks to this: what’s live in the browser today, and hardware-in-the-loop work that currently only runs in a native harness.

In the browser (what you can try now):
ARM7TDMI core borrowed from mGBA, wrapped with the MAD2 memory map and peripherals. One catch: mGBA’s core is little-endian (GBA), while the MAD2 runs the ARM in big-endian mode — so the core needed byte-order handling throughout the memory interface to run Nokia firmware

The DSP is HLE’d. MAD2 pairs the ARM MCU with a TI C54x DSP, and firmware won’t boot without it responding correctly. The HLE is good enough to get real firmware through boot and into normal operation, though I wouldn’t claim it’s faithful beyond what firmware actually exercises

The SIM interface is emulated at the UART level — MAD2 talks to the SIM over its hardware UART, and the emulator presents as a real SIM, characterised by capturing the exchanges from an actual card

Compiles to WASM, works on mobile

Currently booting: 3310, 3410 (with J2ME), 8210, 8250, 8850/8855, 5210, 5110, 6110. The 6210/3210/7110 don’t boot yet.

Native harness only (not in the browser yet):
True C54x co-emulation using the DSP ROM4 mask ROM, which has been dumped from a 5110 (ROM6 hasn’t been dumped — hence the HLE path above). ROM4 boots with the DSP genuinely alive: keypress tones are produced by the DSP’s oscillators driving PCM output, not faked. The open problem is timing — the DSP ran at roughly 4x the ARM core clock, and getting the co-emulation timing right is impacting tone sound quality.
Dumping ROM v6 is proving difficult, TI and Nokia protected the lower mask rom from reading.

An ESP32-based SIM bridge that pipes SIM comms from the emulator to a physical SIM card, so firmware can talk to a real card

A DSP bridge (WIP) that lets the emulator drive the real DSP in a real phone — commands go over MBUS to a custom MADos build running on the handset. It works, but as you’d imagine over 9600 baud, it’s glacially slow

Honest disclosure: a lot of the implementation was AI-assisted. It’s a passion project with zero commercial value and I don’t have unlimited hours, so I used the tools that let me actually finish it. The reverse engineering and architecture calls are where the real work was.

Live: https://retro-phone.com

Source: https://github.com/djr-747/nokia-dct3-emulator

Today I am announcing two new cassettes for the HC-77B emulator. Both available from the projects GitHub page: https://github.com/tmcd35/HomeComp

Cassette 1 - Advanced Monitor Tools - contains three programs. The first is an extension to the main system ROM. This gives a text based command line interface. There is also a very basic line based text editor for entering 6502 assembler code and then a simple 6502 assembler.

Cassette 2 - contains a version of the Tiny BASIC programming language very loosely based on LLL BASIC as described in early 1977 issues of Interface magazine. The Interpreter uses about 3K of RAM and leaves just under 512b for user programs.

https://reddit.com/link/1ugyshr/video/q3g6aznyts9h1/player

https://github.com/tmcd35/HomeComp/tree/master/releases/hc-77b

New version to download. Corrected an issue with the cassette file handling routines. Previously if you didn't eject a cassette properly after use you ran a significant risk of loosing any data being written. Now cassette handling is more immediate and ensures file contents are updated correctly even if you quit the emulator with the tape still in the drive.