AVR Standalone Programmer

Standalone AVR Programmer

A standalone, SD card based programmer for AVR microcontrollers. The device is built around an ATmega328P and programs a target without requiring a computer during normal use. A 20×4 I²C LCD and physical buttons provide a simple on-device interface for selecting firmware.

What it does

• Reads Intel HEX firmware files from an SD card.
• Lets you select a firmware file using the LCD and buttons.
• Checks the HEX file before programming, including its records and checksums, and checks that its address range fits the target's flash.
• Programs the target over ICSP, then reads the firmware back and verifies it against the selected file.
• Identifies supported AVR targets by their device signature and uses the corresponding flash and page information.

The current firmware configuration enables SD card support and ICSP programming. The source also contains options for high-voltage serial and parallel programming, but these modes are disabled in the current configuration.

My contribution

This project is based on Nick Gammon's ATmega HEX uploader. I adapted it into a self-contained device by integrating a 20×4 I²C LCD and button-based interface, designing a custom PCB in KiCad, and adding an SD card workflow for selecting and programming firmware without a PC.

Hardware and software

• Programmer MCU: ATmega328P, configured for a 16 MHz clock
• Target interface: ICSP (current build configuration)
• Firmware storage: SD card with Intel HEX files in the root directory
• User interface: 20×4 I²C LCD and buttons
• Firmware development: PlatformIO with the Arduino framework
• PCB design: KiCad project files in PCB/

Building the firmware

Open the software directory as a PlatformIO project and build the ATmega328P environment. The project uses the LiquidCrystal_I2C library; the SD card support is provided by SdFat.

Place supported .HEX firmware files in the SD card's root directory. The device lists up to ten matching files for selection.