Хост-контроллер USB2.0: список регистров

  Unused

  FRAME_NUMBER

This is incremented when HcFmRemaining is re-loaded. It will be rolled over to 0x0 after 0x0ffff.
When entering the USBOPERATIONAL state, this will be incremented automatically.
The content will be written to HCCA after HC has incremented the FrameNumber at each frame boundary and sent a SOF but before HC reads the first ED in that Frame.
After writing to HCCA, HC will set the StartofFrame in HcInterruptStatus.

HCD (HC)

Команда U-Boot для чтения регистра

Bit fields structure

typedef union  o_hcfmnumber
{
  struct
  {
   unsigned frame_number : 16;
   unsigned unused0 : 16;
  } b;
   unsigned long w;
} O_HcFmNumber