Хост-контроллер USB2.0: список регистров

  POTPGT

Power On To Power Good Time
This byte specifies the duration HCD has to wait before accessing a powered-on port of the Root Hub.
It is implementation-specific.
The unit of time is 2 ms.
The duration is calculated as POTPGT * 2ms.

  Unused

  NO_OVER_CURRENT_PROTECTION

This bit describes how the overcurrent status for the Root Hub ports are reported.
When this bit is cleared, the OverCurrentProtectionMode field specifies global or per-port reporting.

0: Over-current status is reported collectively for all downstream ports.
1: No overcurrent protection supported.

  OVER_CURRENT_PROTECTION_MODE

This bit describes how the overcurrent status for the Root Hub ports are reported.
At reset, these fields should reflect the same mode as PowerSwitchingMode.

This field is valid only if the NoOverCurrentProtection field is cleared.
0: Over-current status is reported collectively for all downstream ports.
1: Over-current status is reported on per-port basis.

  DEVICE_TYPE

This bit specifies that the Root Hub is not a compound device.
The Root Hub is not permitted to be a compound device.
This field should always read/write 0.

  POWER_SWITCHING_MODE

This bit is used to specify how the power switching of the Root Hub ports is controlled.
It is implementation-specific.
This field is only valid if the NoPowerSwitching field is cleared.


0: All ports are powered at the same time.
1: Each port is powered individually.
This mode allows port power to be controlled by either the global switch or per-port switching.
If the PortPowerControlMask bit is set, the port responds only to port power commands(Set/ClearPortPower).
If the port mask is cleared, then the port is controlled only by the global power switch (Set/ClearGlobalPower).

  NO_POWER_SWITCHING

These bits are used to specify whether power switching is supported or ports are always powered.
It is implementation-specific.
When this bit is cleared, the PowerSwitchingMode specifies global or per-port switching.
0: Ports are power switched.
1: Ports are always powered on when the HC is powered on.

  NUMBER_DOWN_STREAM_PORTS

These bits specify the number of downstream ports supported by the Root Hub.
It is implementation-specific. The minimum number of ports is 1.
The maximum number of ports supported.

HCD (HC)

Команда U-Boot для чтения регистра

Bit fields structure

typedef union  o_hcrhdescriptora
{
  struct
  {
   unsigned number_down_stream_ports : 8;
   unsigned no_power_switching : 1;
   unsigned power_switching_mode : 1;
   unsigned device_type : 1;
   unsigned over_current_protection_mode : 1;
   unsigned no_over_current_protection : 1;
   unsigned unused0 : 11;
   unsigned potpgt : 8;
  } b;
   unsigned long w;
} O_HcRhDescriptorA