Хост-контроллер USB2.0: список регистров

  BHED_31_4

The HcBulkHeadED register contains the physical address of the first Endpoint Descriptor of the Bulk list.
HC traverses the Bulk list starting with the HcBulkHeadED pointer.
The content is loaded from HCCA during the initialization of HC.

  BHED_3_0

BHED[3:0]
Because the general TD length is 16 bytes, the memory structure for the TD must be aligned to a 16-byte boundary.
So the lower bits in the PCED, through bit 0 to bit 3 must be zero in this field.

HCD (HC)

Команда U-Boot для чтения регистра

Bit fields structure

typedef union  o_hcbulkheaded
{
  struct
  {
   unsigned bhed_3_0 : 4;
   unsigned bhed_31_4 : 28;
  } b;
   unsigned long w;
} O_HcBulkHeadED