Working with C/C++

This chapter contains the following sections. Please read as needed:

• Setting Up the Development Environment
• Example

Setting Up the Development Environment

Please refer to the Install and Configure Pico C/C++ Development Environment Tutorial to download and install the Pico VSCode.

Example

The C/C++ examples are located in the examples\C directory of the example package.

Example	Basic Program Description	Dependency Library
01_USB	PIO‑USB emulation of USB device/host examples	-
02_RGB	Onboard RGB LED example	-

01_USB

• The examples are modified from sekigon-gonnoc's Pico-PIO-USB.

• Example version: 0.5.3

• PICO SDK version: 2.2.0

Example Description

• usb_device

  • Example path: examples/usb_device
  • Uses PIO‑USB to emulate an HID keyboard/mouse device. After the computer recognizes it, the mouse cursor moves periodically.

• host_hid_to_device_cdc

  • Example path: examples/host_hid_to_device_cdc
  • Uses PIO‑USB as a host to read HID reports from a keyboard/mouse and outputs them to the computer's serial port via native USB CDC.
  • Note: When compiling this example, you must comment out the return statements in the file SDK\lib\tinyusb\src\portable\raspberrypi\pio_usb\hcd_pio_usb.c, as shown below:

    bool hcd_edpt_abort_xfer(uint8_t rhport, uint8_t dev_addr, uint8_t ep_addr) {
      uint8_t const pio_rhport = RHPORT_PIO(rhport);
      // return pio_usb_host_endpoint_abort_transfer(pio_rhport, dev_addr, ep_addr);
    }      
    
    uint32_t hcd_frame_number(uint8_t rhport) {
      (void) rhport;
      // return pio_usb_host_get_frame_number();
    }  

Hardware Connection

• Connect the board to the computer using a USB cable

Operation Result

• usb_device

  PIO‑USB emulates a mouse and moves the mouse cursor every 0.5 seconds.

  

• host_hid_to_device_cdc

  Similar to capture_hid_report, prints mouse/keyboard reports from the host port to the device port's CDC.

  

02_RGB

Example Description

• Uses GPIO16 to drive a WS2812B RGB LED via PIO, cycling through colors.

Hardware Connection

• Connect the board to the computer using a USB cable.

Operation Result

• After flashing, the WS2812B RGB LED continuously fades through red, green, and blue.