Note: The IU5JAE firmware requires the "Plus" version of the radio (ATS-20+) or a specific hardware modification (adding a 3.3V level shifter) for the original ATS-20.
Before downloading, identify your hardware. The original ATS20 uses a blue PCB and an ATmega328. The ATS20+ uses a red PCB and often includes a battery charging IC. Do not mix them up.
Here are the three major firmware branches:
Q: Can I update ATS20 firmware via USB-C? A: Rarely. Most ATS20 units only use the USB port for charging. You need an external programmer via the ICSP header.
Q: Will custom firmware increase the battery life? A: Yes. Many custom firmware builds allow the ATmega328 to enter "sleep mode" when the screen backlight is off, extending runtime from 6 hours to nearly 10.
Q: Does this work on the ATS20 Pro? A: Yes, but verify the main chip. If it uses an ATmega328, the process is identical. If it uses an ARM chip (STM32), you need different firmware.
Q: What is the best source for ATS20 firmware files? A: GitHub repositories by pu2clr, LeviTheDev, and gilchrist-tech are the most reliable. Avoid "file download" sites that bundle malware.
Have you flashed your ATS20? Share your experience and favorite firmware build in the comments below.
The ATS20 firmware has become a cornerstone for radio enthusiasts looking to unlock the full potential of their SI4732-based all-band receivers. While these devices are affordable and compact, it is the community-driven firmware that transforms them from basic radios into versatile tools for DXing (long-distance listening).
In this article, we’ll dive into what makes the ATS20 firmware special, how it improves your hardware, and why the "v2" or "ATS20+" variants are the current gold standard. What is the ATS20 Receiver?
The ATS20 is a portable SI4732-based radio that typically covers FM, AM, and Shortwave (SW) bands. Out of the box, the factory firmware is often functional but limited—lacking fine-tuning controls, SSB (Single Side Band) stability, or a user-friendly interface. ats20 firmware
The ATS20 firmware (often based on the open-source work of Ricardo Caratti and later modified by others) bridges this gap by utilizing the full processing power of the onboard Arduino/Atmega328p chip. Key Features of Enhanced ATS20 Firmware
Upgrading your firmware isn't just about bug fixes; it’s about adding professional-grade features to a budget device:
SSB (Single Side Band) Support: This is the "holy grail" for many users. Advanced firmware allows you to listen to amateur radio (HAM) operators, utility stations, and maritime communications by enabling LSB (Lower Side Band) and USB (Upper Side Band) modes.
Fine Tuning Steps: Custom firmware often introduces variable tuning steps (1kHz, 5kHz, 10kHz, etc.), allowing you to zero in on a weak signal with precision.
Improved BFO (Beat Frequency Oscillator): This allows for better SSB demodulation, reducing "chipmunk voices" and making voice transmissions clear.
OLED Optimization: Many custom builds optimize the 0.96-inch OLED screen to show signal strength (S-meters), battery levels, and bandwidth settings more clearly.
Band Scanning: Some versions include a rudimentary scan feature to find active frequencies across the shortwave spectrum. The "ATS20+" and "v2" Evolution
If you are searching for firmware today, you’ll likely encounter the ATS20+ (v2). This version often features a larger battery, better filtering, and, crucially, firmware that supports a wider frequency range (sometimes down to 150kHz for Longwave).
The firmware for the ATS20+ is specifically tuned to handle the slightly different hardware layout and rotary encoder behavior found in the updated models. How to Update Your ATS20 Firmware
Most ATS20 radios use an Arduino-compatible microcontroller. To update: Note: The IU5JAE firmware requires the "Plus" version
Hardware Connection: Connect the radio to your PC via a USB cable (ensure your radio has a USB-to-serial chip like the CH340). The Software: Use the Arduino IDE or XLoader.
The Code: Download the .ino or .hex file from a reputable source like GitHub (search for "SI4735-Arduino-Library-master" by PU2CLR).
Flash: Select the correct COM port and board (usually "Arduino Nano") and hit upload. Why Enthusiasts Love It
The ATS20 firmware community is highly active. Users frequently share modified versions that change the UI colors (if using a compatible screen), add "favorite" station memories, or improve the AGC (Automatic Gain Control) for better performance during high-interference periods. Conclusion
The ATS20 firmware is more than just code—it’s the "soul" of the radio. By moving away from the stock software, you turn a $40 gadget into a surprisingly capable receiver that rivals much more expensive units in the amateur radio world.
The ATS20 (often called the ATS-20+) is a portable all-band radio based on the Si4732/Si4735 chip and an Arduino-compatible microcontroller. Updating the firmware is a popular way to add features like SSB (Single Side Band) support, RDS, and better battery monitoring. Preparation & Required Tools Before starting, ensure you have the following:
A PC with the CH340/CH341 drivers installed (common for many ATS20 units).
USB Data Cable: Use a high-quality USB-C or Mini-USB cable (depending on your board).
Flashing Software: Common choices include AVRDUDESS or the Arduino IDE.
External Programmer (Optional but Recommended): Many users report that the onboard USB port doesn't allow direct flashing. In these cases, a USBasp V2 programmer or using an Arduino Uno as an ISP is required. Standard Flashing Procedure (Via USB) Before downloading, identify your hardware
If your unit has a working bootloader, you can often update it directly via USB:
Title: ATS20 Firmware Deep Dive: Which one gives the best performance?
Posted by: RadioRookie42
Hey everyone,
I’ve been tinkering with the ATS20 (Si5351 + Si4732 based SDR receiver) for a few months now. While the stock firmware is fine, I recently dove into the custom firmware options, and wow – it’s a completely different radio.
If you’re new to the ATS20, here’s a breakdown of the firmware scene I wish I had from day one.
Run a verification check. If AVRDUDE reports "0 errors," disconnect the programmer, reassemble the radio, and turn it on.
The ATS-20 and its upgraded sibling, the ATS-20X, have become ubiquitous in the world of amateur radio and shortwave listening. As incredibly affordable, portable HF (High Frequency) receivers, they offer a lot of functionality for the price. However, many users find the out-of-box experience lacking—quirky menus, limited frequency steps, or a user interface that feels unfinished.
This is where the world of ATS20 Firmware steps in, transforming a cheap gadget into a capable receiver.
If your radio arrived from China last week, it likely has outdated firmware. Here is why you should flash a new version immediately:
The ATS20 is not just a closed commercial product; it is largely built on the open-source PU2CLR SI4735 library.