1. Introduction

With it's massive community and extensive set of supported boards and libraries, the Arduino development environment has become a force of nature. Here are the steps to set up and use the Arduino IDE for the PX-HER0 board.

2. Download and install the Arduino IDE

Go to THIS page to download and install Arduino 1.8.10 or newer.

3. Install support for STM32 based boards

Support for STM32 boards are provided HERE.

Open the Preferences dialog in the Arduino IDE:

File > Preferences Ctrl+Comma

Add a link to the stm32duino JSON file in the "Additional Boards Manager URLs" field:

https://github.com/stm32duino/BoardManagerFiles/raw/main/package_stmicroelectronics_index.json

More than one link (URL) can be added by using the button next to the text field.

Now open the Boards Manager window in the Arduino IDE:

Tools > Board: "xxx" > Boards Manager...

Type "STM32" into the search bar to narrow down the list of packages and install the "STM32 MCU based boards by STMicroelectronics" package.

4. Specify the PX-HER0 board

Select the PX-HER0 board from the list of supported boards:

Tools > Board: "xxx" > STM32 boards groups > Generic STM32L0 series
Tools > Board part number: "xxx" > PX-HERO

Options can be specified for the PX-HER0 board in sub menus:

Select "CDC (generic 'Serial supersede U(S)ART)" as the USB interface. This will configure the Arduino firmware to stream all Serial communication over USB. We will use the USB1 connector on the PX-HER0 board for serial communication.

Select "STM32CubeProgrammer (DFU)" as the upload method. The Arduino IDE will use the STM32CubeProgrammer command line software to program the STM32 via it's bootloader in ROM. We will use the USB1 connector on the PX-HER0 board to program the STM32 too.

5. Build a sketch

Open the "serial_hello_world" sketch. It is located here:

px-fwlib/boards/arm/stm32/px_hero/arduino/examples/serial_hello_world/serial_hello_world.ino

Build the sketch:

Sketch > Verify/Compile Ctrl+R

7. Uploading a sketch to the PX-HER0 board

Connect the BOOT jumper on the PX-HER0 board. It will pull the BOOT0 pin of the STM32 low and the built-in bootloader will be activated upon reset or power up.

Press the RST button. This will activate the bootloader.

Upload the sketch:

Sketch > Upload Ctrl+U

After the sketch has been uploaded, the program will imediately start to run.

Open Tera Term and connect to the virtual serial port created the PX-HER0 board. The program will wait for the PC to connect and then start to send the string "Hello World!" once a second:

Success!!

You can keep the BOOT jumper connected while developing. When you want to upload a new sketch, tap the RST button and the STM32 will go back into boot mode, ready to receive a new program.

remove the BOOT jumper when you are finished. Otherwise, the STM32 will appear "dead", because it is in boot mode and not executing your program.

8. Digital pin mapping

The PX-HER0 board pins are mapped in THIS file. It is duplicated here for easy offline viewing:

px-fwlib/boards/arm/stm32/px_hero/arduino/variants/STM32L0xx/L072R(B-Z)T_L073R(B-Z)T_L083R(B-Z)T/variant_PX_HER0.h

Here is the map table:

Digital pin	Alias 1	Alias 2
0	PA6	PX_GPIO0
1	PA5	PX_GPIO1
2	PA1	PX_GPIO2
3	PA0	PX_GPIO3
4	PC3	PX_GPIO4
5	PC2	PX_GPIO5
6	PC1	PX_GPIO6
7	PB7	PX_GPIO7
8	PH0	PX_USR_LED
9	PC0	PX_LCD_BTN_1_LT
10	PH1	PX_LCD_BTN_2_RT
11	PC13	PX_LCD_BTN_3_UP
12	PC12	PX_LCD_BTN_4_DN
13	PA15	PX_LCD_BTN_5_YES
14	PC9	PX_LCD_BTN_6_NO
15	PA8	PX_USB_DET
16	PB11	PX_LCD_RS
17	PB12	PX_LCD_BACKLIGHT
18	PC6	PX_PWM_BUZZER
19	PC7	PX_VBAT_MEAS_EN
20	PC8	PX_PWR_HOLD
21	PA9	PX_UART1_TX
22	PA10	PX_UART1_RX
23	PA2	PX_UART2_TX
24	PA3	PX_UART2_RX
25	PC10	PX_UART4_TX
26	PC11	PX_UART4_RX
27	PB8	PX_I2C1_SCL
28	PB9	PX_I2C1_SDA
29	PB6	PX_SPI1_CS
30	PB3	PX_SPI1_SCK
31	PB5	PX_SPI1_MOSI
32	PB4	PX_SPI1_MISO
33	PB2	PX_SPI2_CS_SF
34	PB10	PX_SPI2_CS_LCD
35	PD2	PX_SPI2_CS_SD
36	PB13	PX_SPI2_SCK
37	PB15	PX_SPI2_MOSI
38	PB14	PX_SPI2_MISO
39	PA4	PX_DAC1
40	PB0	PX_ADC0
41	PC5	PX_ADC1
42	PC4	PX_ADC2
43	PA7	PX_ADC3
44	PB1	PX_ADC_VBAT

Thus the following code lines are all equivalent:

digitalWrite(8,           HIGH);
digitalWrite(PH0,         HIGH);
digitalWrite(PX_USR_LED,  HIGH);
digitalWrite(LED_BUILTIN, HIGH);

9. Next step

Several examples are provided to demonstrate different parts of the board. Click HERE to proceed...