commit 6459fe2f0266956ef908aed4598f75497d27cedd Author: Dejvino Date: Mon Feb 23 22:28:30 2026 +0100 first commit diff --git a/README.md b/README.md new file mode 100644 index 0000000..753ace4 --- /dev/null +++ b/README.md @@ -0,0 +1,105 @@ +# Raspberry Pi 1 Bare-Metal Synthesizer + +This project turns an original Raspberry Pi (Model 1 B/B+, Zero, or Zero W) into an instant-on, single-voice synthesizer that runs without any operating system (bare metal). + +It boots in under two seconds and produces sound and graphics with minimal external components. + +## Features + +- **Instant-On**: Boots directly into the synth application in ~1-2 seconds. +- **Audio Output**: Generates a sawtooth waveform on the 3.5mm composite audio jack. +- **Video Output**: Displays a simple amplitude visualizer on the composite video output. +- **Looped Melody**: Plays a pre-programmed random melody, no input required. + +## Requirements + +### Hardware + +- **Raspberry Pi**: Model 1 (A, B, B+), Pi Zero, or Pi Zero W. This code is for the **BCM2835** SoC and will **not** work on Pi 2, 3, 4, or 5. +- **SD Card**: A microSD or standard SD card (depending on your Pi model), 1GB is more than enough. +- **Power Supply**: A standard 5V micro-USB power supply. +- **Audio Cable**: A 3.5mm audio cable to connect to headphones or a speaker. + +### Software + +- **ARM Cross-Compiler**: The `arm-none-eabi-gcc` toolchain is required to build the kernel. +- **Raspberry Pi Firmware**: You need the `bootcode.bin` and `start.elf` files from the official Raspberry Pi firmware repository. + +## Quick Start with Scripts + +For a fast and easy setup, you can use the provided automation scripts. + +1. **Build the kernel**: + ```sh + ./build.sh + ``` + This will compile the C and Assembly code and create the `kernel.img` file. + +2. **Deploy to SD Card**: + Insert your FAT32-formatted SD card. Find its device name (e.g., `/dev/sdX` or `/dev/mmcblkX`) and mount point. + + ```sh + # Example: ./deploy.sh /media/user/RASPIBOOT + ./deploy.sh + ``` + This script copies `kernel.img`, `bootcode.bin`, and `start.elf` to the SD card and then safely unmounts it. + +## Manual Setup and Deployment + +### 1. Install Toolchain + +On Debian/Ubuntu-based systems, you can install the cross-compiler with: +```sh +sudo apt-get update +sudo apt-get install gcc-arm-none-eabi binutils-arm-none-eabi +``` + +### 2. Get Raspberry Pi Firmware + +The Pi's GPU first loads firmware from the SD card before handing control to the ARM core. You need two files: + +- `bootcode.bin`: The second-stage bootloader. +- `start.elf`: The GPU firmware. + +You can download them from the official Raspberry Pi firmware repository. Make sure to grab the files from the `boot` directory. For this project, you only need these two files. + +Place them in the root of this project directory so the `deploy.sh` script can find them. + +### 3. Build the Kernel + +With the toolchain installed, compile the synthesizer by running `make`: +```sh +make +``` +This command uses the `Makefile` to compile `boot.S` and `kernel.c`, linking them into a final binary image named `kernel.img`. + +### 4. Prepare the SD Card + +Your SD card must be formatted with a **FAT32** filesystem. Most new SD cards are already formatted this way. The partition should also have the "boot" or "lba" flag set, which is standard for bootable Raspberry Pi cards. + +### 5. Deploy to SD Card + +Mount the SD card and copy the three essential files to its root directory: + +- `bootcode.bin` (from the firmware repo) +- `start.elf` (from the firmware repo) +- `kernel.img` (generated by the `make` command) + +After copying, unmount the SD card safely. + +## Hardware Connections + +1. **SD Card**: Insert the prepared SD card into your Raspberry Pi. +2. **Audio**: Connect headphones or a speaker to the 3.5mm audio jack. +3. **Video (Optional)**: Connect a composite video cable from the RCA jack (on Model B) or the 3.5mm jack (on later models) to a compatible display. +4. **Power**: Connect the 5V micro-USB power supply. The Pi will boot immediately. + +## Usage + +Once powered on, the synthesizer will automatically start playing a random melody loop. The composite video output will show a simple red bar that visualizes the audio amplitude. + +There is no user input required for this version of the code. + +--- + +*This project is for educational purposes and demonstrates low-level hardware control on the BCM2835 SoC.* \ No newline at end of file