Usbpicprog: The Open-Source Hardware Champion for PIC Microcontrollers
Usbpicprog is a completely free, open-source Microchip PIC microcontroller programmer designed for the USB port. Developed by Frans Schreuder, the ecosystem merges minimalist hardware, open firmware, and a cross-platform desktop application into a single, high-utility tool for embedded developers.
Unlike proprietary alternatives, the Usbpicprog GitHub Repository shares its complete PCB layout, allowing developers to build their own hardware from scratch. This makes it a popular tool for students, makers, and professional hardware engineers seeking an inexpensive way to flash target devices. The Three Core Pillars of Usbpicprog
The architecture is divided into three distinct segments that handle different aspects of the programming cycle:
+——————————————————-+ | PC SOFTWARE | | (wxWidgets GUI / CLI on Windows, Mac, or Linux) | +———————————–+——————-+ | (via USB Cable) v +——————————————————-+ | HARDWARE BOARD | | (PIC18F2550 Microcontroller + DC/DC Charge Pump) | +———————————–+——————-+ | (via Firmware Code) v +——————————————————-+ | TARGET DEVICE | | (Flashing Hex Files to 12F, 16F, 18F, etc.) | +——————————————————-+ 1. Hardware Architecture
The hardware is designed for maximum simplicity and affordability. It centers around a single Microchip PIC18F2550 microcontroller, which features native, on-board USB communication capabilities.
The Circuit: It utilizes a basic charge pump DC/DC converter to generate the necessary 13V programming voltage (VPP) required by target microcontrollers.
The Design: The entire schematics and layout are created in KiCad—the open-source EDA suite—and are distributed freely in Gerber and PDF formats. Developers can opt to build a surface-mount (SMD) version, a through-hole version, or a variant with an integrated ZIF socket. 2. Embedded Firmware
The firmware running inside the central PIC18F2550 controls the timing and high-level programming logic. It splits into two independent roles:
The Bootloader: It implements a modified version of Microchip’s PICDem FS USB bootloader. It only needs to be flashed to the main chip once using a secondary programmer. Once active, the bootloader allows the board to update its own core firmware directly over the USB connection.
The Algorithms: The main firmware code dictates the exact programming algorithms required to flash data onto target microchips securely. 3. Cross-Platform PC Software usbpicprog – a free and open source usb pic programmer
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