Create ADC Applications

Create ADC Applications explains the steps to program a USB Device for audio streaming using the RL-USB Library. Audio applications control speakers, microphones, or other audio devices.

Include into the project and configure the following RL-USB Device Source Files:

1. The library that matches the device core:
   USB_CM1.lib - for Cortex-M1 devices.
   USB_CM3.lib - for Cortex-M3 devices.
   USB_ARM_L.lib - for ARM7 or ARM9 devices.
2. usb_config.c - to configure the USB system.
3. usbd_device family.c(.h) - to configure the device hardware layer.
4. usbd_user_adc.c - to adapt the code to the application needs.
5. USBD_Demo.c - to initialize and connect the USB Device from main().

   ..
   usbd_init();
   usbd_connect(__TRUE);
   ..
   

Applications can be created using existing µVision audio projects. The RL-USB audio examples have a simple function that receives an audio data stream from the host and sends it to a speaker.

1. Copy all files from any folder \ARM\Boards\Vendor\BoardName\RL\USB\Device\Audio to a new folder and open the project *.uvproj with µVision. RTX projects are using the RTX-RTOS, whereas simple Audio projects work without an RTOS. However, the USB configuration does not differ.
2. Open the file usb_config.c and configure the USB device with the Configuration Wizard.
3. Enable USB Device and set the device characteristics.

   

4. Enable Class Support and Audio Device (ADC) and set the characteristics.

   

5. Optionally, adapt the source files usbd_device family.c that contain hardware dependent code and must be adapted to the USB controller.
6. Modify the file usbd_user_adc.c to adapt the code to the application needs.

Note

• The options are explained in Audio Device (ADC) Options.