In order to program the ESP32 on the ULX3S, the PassThru FPGA code needs to first be loaded.
Next, in the Arduino IDE ensure that the Espressif SDK 1.0.1 or later is installed.
If any problems are encountered, consider completely removing old espressif files that may be in one of these directories:
C:\Users\{username}\Documents\Arduino\hardware\
C:\Users\{username}\AppData\Local\arduino15\packages\esp32\
Then re-install the Espressif SDK 1.0.1 fresh from the Board Manager. The following URL may need to be added to the "Additional Boards Manager URLs" list:
https://dl.espressif.com/dl/package_esp32_dev_index.json
Once the Espressif boards are added to the Arduino IDE, select WEMOS LOLIN32 from the ESP32 Ardunio section of the board selection menu.
Find the USB Port used by your ULX3S using Windows Device Manager and ensure it is selected for Tools - Port. Also note other settings:
The blinks app can be selected from File - Examples - 01.Basics - Blink, or use the code below that has Hello World added to serial output.
The ESP32 blinky app:
// the setup function runs once when you press reset or power the board
void setup() {
// initialize digital pin LED_BUILTIN as an output.
pinMode(LED_BUILTIN, OUTPUT); // LED_BUILTIN = 5, this is D22 on the ULX3S
Serial.begin(115200);
}
// the loop function runs over and over again forever
void loop() {
Serial.print("Hello world! Blink on port = ");
Serial.println(LED_BUILTIN);
digitalWrite(LED_BUILTIN, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(LED_BUILTIN, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}
If an error like this is encountered, ensure the passthough app is active on the FPGA:
Serial port COM13
Connecting........_____....._____....._____....._____....._____....._____....._____
A fatal error occurred: Failed to connect to ESP32: Timed out waiting for packet header
In Ardunio, theesptool.exe is used to upload the binary ESP32 files, and is typically found here:
C:\Users\{username}\AppData\Local\Arduino15\packages\esp32\tools\esptool_py\2.6.0\
in WSL (replace build_423515 with your build directory, and ttyS13 with your port):
python esptool.py --chip esp32 \
--port /ttyS13 \
--baud 921600 \
--before default_reset \
--after hard_reset write_flash \
-z \
--flash_mode dio \
--flash_freq 80m \
--flash_size detect 0xe000 /mnt/c/Users/$USER/AppData/Local/Arduino15/packages/esp32/hardware/esp32/1.0.1/tools/partitions/boot_app0.bin \
0x1000 /mnt/c/Users/$USER/AppData/Local/Arduino15/packages/esp32/hardware/esp32/1.0.1/tools/sdk/bin/bootloader_dio_80m.bin \
0x10000 /mnt/c/Users/$USER/AppData/Local/Temp/arduino_build_423515/Blink.ino.bin \
0x8000 /mnt/c/Users/$USER/AppData/Local/Temp/arduino_build_423515/Blink.ino.partitions.bin
or in the bin/ESP32 directory of this respository (assumed git-clone from c:\workspace):
ULXS3_COM=/dev/ttyS13
cd /mnt/c/workspace/ulx3s-examples/bin/esp32
python esptool.py --chip esp32 \
--port $ULXS3_COM \
--baud 921600 \
--before default_reset \
--after hard_reset write_flash \
-z \
--flash_mode dio \
--flash_freq 80m \
--flash_size detect 0xe000 boot_app0.bin \
0x1000 bootloader_dio_80m.bin \
0x10000 Blink.ino.bin \
0x8000 Blink.ino.partitions.bin
See the quick start upload_blinky.sh and upload_blinky.bat
See also Visual Micro Arduino IDE for Visual Studio other ESP32 examples and other ULX3S examples