Working with C/C++

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

Setting Up the Development Environment

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

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 example	-
02_RGB	Onboard RGB LED example	-

Example Description

Board selection
- File path: examples/01_USB/src/pio_usb_configuration.h
- For RP2350-USB-C and RP2350-USB-CM, switch via macro definitions
```
#define RP2350_USB_C 1
#define RP2350_USB_CM 0
```
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

Operation Result

usb_device

Through PIO-USB, the board emulates a mouse and moves the 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.

Example Description

Hardware Connection

Operation Result

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