Answer

The vias should be filled. If they are left open, the solder has the potential to wick into the holes and cause random fallout due to the part skewing on the PCB.

Answer

1. Happy Gecko supports device mode only, other devices support device, host, or OTG.
2. Happy Gecko does not require a crystal oscillator, and can run USB with a 24MHz sysclk.  Other devices require a 48MHz crystal.
3. Happy Gecko also supports low energy USB modes, which reduces current consumption when USB is idle. See AN0886: Happy Gecko Low Energy USB Overview for more information on these modes. Application notes can be found in Simplicity Studio or at www.silabs.com/32bit-appnotes.

Answer

There are two USB audio examples (USB Audio Class 1.0) for the EFM32. These examples can be found using the Software Examples tile in Simplicity Studio.  The two examples are:

usbdheadphone

usbdmicrophone

Both of these examples are available for the EFM32GG, EFM32LG, and EFM32WG Development Kits.

These examples can also be found on disk here by default:

usbdheadphone

C:\SiliconLabs\SimplicityStudio\v3\developer\sdks\efm32\v2\kits\EFM32LG_DK3650\examples\usbdheadphone

C:\SiliconLabs\SimplicityStudio\v3\developer\sdks\efm32\v2\kits\EFM32GG_DK3750\examples\usbdheadphone

C:\SiliconLabs\SimplicityStudio\v3\developer\sdks\efm32\v2\kits\EFM32WG_DK3850\examples\usbdheadphone

usbdmicrophone

C:\SiliconLabs\SimplicityStudio\v3\developer\sdks\efm32\v2\kits\EFM32LG_DK3650\examples\usbdmicrophone

C:\SiliconLabs\SimplicityStudio\v3\developer\sdks\efm32\v2\kits\EFM32GG_DK3750\examples\usbdmicrophone

C:\SiliconLabs\SimplicityStudio\v3\developer\sdks\efm32\v2\kits\EFM32WG_DK3850\examples\usbdmicrophone

If using these USB audio examples for EFM32HG USB devices, it needs to mask off the LEMOSCCTRL bit field in USB_CTRL register. 

  /* Initialize and start USB device stack. */
  USBD_Init(&usbInitStruct);
#ifdef _USB_CTRL_LEMOSCCTRL_MASK
  USB->CTRL &= ~_USB_CTRL_LEMOSCCTRL_MASK;
#endif

Answer

We've seen cases where a long USB cable causes this problem. Try using a shorter cable.

Answer

It is located in the folder for the USB composite device firmware example.

For the Giant Gecko STK:

C:\SiliconLabs\SimplicityStudio\v3\developer\sdks\efm32\v2\kits\EFM32GG_STK3700\examples\usbdcomposite\Silabs-CDC_Install.zip

Answer

In our examples when performing a USB core reset, we perform the USB soft reset, wait 1 µs, then poll AHBIDLE. Ensure the USB soft reset is performed before polling AHBIDLE.

Here is our USB core reset in its entirety:

void USBHAL_CoreReset( void ) 
{ 
   USB->PCGCCTL &= ~USB_PCGCCTL_STOPPCLK; 
   USB->PCGCCTL &= ~(USB_PCGCCTL_PWRCLMP | USB_PCGCCTL_RSTPDWNMODULE); 

   /* Core Soft Reset */ 
   USB->GRSTCTL |= USB_GRSTCTL_CSFTRST; 
   while ( USB->GRSTCTL & USB_GRSTCTL_CSFTRST ) {} 

   USBTIMER_DelayUs( 1 ); 

   /* Wait for AHB master IDLE state. */ 
   while ( !( USB->GRSTCTL & USB_GRSTCTL_AHBIDLE ) ) {} 
} 

This code can be found in Simplicity Studio > Application Notes > AN0065 EFM32 as USB Device > Import Project > STK3700_usb_device.slsproj (or different extension depending on your preferred IDE) > OK.

After this project opens in the Simplicity Studio IDE, the source code can be found in emusb\em_usbhal.c > USBHAL_CoreReset().

Answer

Environmental & Regulatory documents are made available through MDDS "Material Declaration Data Sheet" via the RFI Portal (free registration required).  This portal provides the following documentation for many of our devices:

• Detailed Device Composition (MDDS)
• Halogen Free Certificate of Compliance
• Material Test Results
• Pb Free Confirmation
• PFOS Certificate of Compliance
• PFOS/PFOA Free Confirmation
• REACH Declaration
• RoHS Certificate of Compliance

To access this content, follow the initial instructions provided in the Knowledge Base article Qualification report up to step # 7.  At that point, navigate to and "checkmark" one or more of the following options - captured as an example for an EFM32GG MCU:

After making your selections, click the red arrow to query the RFI Portal for your desired documentation and generate your search results:

Answer

The material composition of any particular EFM32 MCU is available in the Detailed Device Composition (MDDS) document for that part.

To access this information, follow the procedure detailed in the Knowledge Base article How to obtain Environmental and Regulatory documents for Silicon Labs devices.