Arduino¶

OpenSiFli has a beta Arduino core for SF32 based on Zephyr: OpenSiFli/ArduinoCore-zephyr. It publishes the sifli:sf32lb52 Arduino package, appears in Boards Manager as SiFli Serial Boards, and currently targets the SiFli SF32LB52 DevKit LCD board.

This is a good path for sketches, quick peripheral checks, demos, and early prototypes. For production firmware, Bluetooth stack tuning, graphics-heavy applications, low-power optimization, or custom board bring-up, use SiFli-SDK.

What You'll Need¶

Hardware

• SiFli SF32LB52 DevKit LCD.
• A USB Type-C data cable connected to the board's USB-to-UART path.
• A computer running Windows, macOS, or Linux.

Software

• Arduino IDE 2.x or Arduino CLI.
• The OpenSiFli sifli:sf32lb52 Arduino package.
• A serial monitor.

Install the Board Package¶

Open Arduino IDE > Settings and add this URL to Additional Boards Manager URLs:

https://github.com/OpenSiFli/ArduinoCore-zephyr/releases/latest/download/package_sifli_index.json

For users in mainland China, use the mirrored package index:

https://downloads.sifli.com/github_assets/OpenSiFli/ArduinoCore-zephyr/releases/latest/download/package_sifli_index_cn.json

Then open Boards Manager, search for SiFli Serial Boards, and install the sifli:sf32lb52 platform.

With Arduino CLI:

arduino-cli core install sifli:sf32lb52 \
  --additional-urls https://github.com/OpenSiFli/ArduinoCore-zephyr/releases/latest/download/package_sifli_index.json

For the China mirror:

arduino-cli core install sifli:sf32lb52 \
  --additional-urls https://downloads.sifli.com/github_assets/OpenSiFli/ArduinoCore-zephyr/releases/latest/download/package_sifli_index_cn.json

Select the Board¶

In Arduino IDE, select:

SiFli SF32LB52 DevKit LCD

The board FQBN is:

sifli:sf32lb52:sf32lb52devkitlcd

The OpenSiFli board definition maps this Arduino board to the Zephyr target sf32lb52_devkit_lcd and the variant sf32lb52_devkit_lcd_sf32lb525uc6.

Choose Build Options¶

The core exposes two important menus:

Start with Standard and Dynamic unless you are debugging loader behavior.

Put the Board in Serial Download Mode¶

OpenSiFli documents that first use requires the board to be in serial download mode. Use the boot/reset sequence for the SF32LB52 DevKit LCD, then upload from Arduino IDE or CLI.

The upload tool is sftool.

Upload a Serial Smoke Test¶

Start with serial output. It confirms upload, reset, runtime startup, and console routing without depending on LED polarity:

void setup() {
  Serial.begin(115200);
}

void loop() {
  Serial.println("Hello from SF32 Arduino");
  delay(1000);
}

Upload from Arduino IDE, or use Arduino CLI:

arduino-cli compile \
  --fqbn sifli:sf32lb52:sf32lb52devkitlcd:link_mode=dynamic \
  /path/to/YourSketch

arduino-cli upload \
  -p /dev/cu.usbserial-XXXX \
  --fqbn sifli:sf32lb52:sf32lb52devkitlcd:link_mode=dynamic \
  /path/to/YourSketch

Replace /dev/cu.usbserial-XXXX with your board's serial port. On Windows, use the matching COM port. On Linux, use the matching /dev/ttyUSB* or /dev/ttyACM* port.

Open the Serial Monitor at 115200 baud. In Standard build mode, the sketch should print one line per second. In Debug build mode, open the Zephyr shell and run:

sketch

Upload Blink¶

The SF32LB52 DevKit LCD variant defines:

#define LED_BUILTIN 13

Try Blink after the serial smoke test succeeds:

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
  digitalWrite(LED_BUILTIN, HIGH);
  delay(500);
  digitalWrite(LED_BUILTIN, LOW);
  delay(500);
}

Troubleshooting¶

What SiFli Team Should Finish¶

To make this Arduino path production-quality for public users, SiFli should complete the following work:

• Stability statement: define what “beta” means, what APIs are supported today, and what must be considered unstable.
• Release matrix: publish a table mapping Arduino package versions to Zephyr downstream commits, loader firmware versions, sftool versions, and supported board revisions.
• Board list: document every supported board, FQBN, Zephyr target, variant directory, chip variant, flash size, PSRAM size, and LED_BUILTIN value.
• Board Manager screenshots: show the exact package URL field, Boards Manager search result, board menu, build mode menu, link mode menu, and port selection.
• Download mode instructions: document the exact button/reset/power sequence for SF32LB52 DevKit LCD, with photos if possible.
• Serial routing: specify the default UART, baud rate, USB connector, driver expectations, and how this differs between Standard and Debug modes.
• Loader lifecycle: explain when users only upload sketches, when they must update the loader, and how to recover after a bad loader.
• Dynamic vs. static guidance: explain memory, startup, debugging, and compatibility tradeoffs for each link mode.
• API support table: list status for GPIO, analog read/write, PWM, UART, I2C, SPI, timers, interrupts, filesystem, display, BLE, Wi-Fi stubs, USB, and low power.
• Known library compatibility: state which Arduino libraries are tested, which are expected to work, and which are known not to work.
• Example suite: include verified Serial, Blink, GPIO input, PWM fade, I2C scan, SPI loopback or display, UART echo, and BLE examples.
• Troubleshooting logs: provide known-good upload logs, boot logs, shell output, and common error messages with fixes.
• Issue template: add a bug-report checklist that asks for board revision, package version, FQBN, build mode, link mode, OS, Arduino IDE/CLI version, serial log, and upload log.
• Graduation criteria: define what must be true before removing the beta warning from this page.