Регистры H616: OHCI Periodic Start Register

O_HcPeriodicStart

9.5.3. OHCI Periodic Start Register - адрес: 0x5200440 0x5310440 0x5311440 (смещение: 0x0440)

Хост-контроллер USB2.0: список регистров

31 |•|•|•|•|•|•|•|•|•|•|•|•|•|•|•|•| 16
15 |•|•|•|•|•|•|•|•|•|•|•|•|•|•|•|•| 00

Unused

Bits 31 : 14

PERIODIC_START

Bits 13 : 0
R/W (R)
0x0

After a hardware reset, this field is cleared. This is then set by HCD during the HC initialization.
The value is calculated roughly as 10% off from HcFmInterval.
A typical value will be 0x2A3F (0x3e67).
When HcFmRemaining reaches the value specified, processing of the periodic lists will have priority over Control/Bulk processing.
HC will therefore start processing the Interrupt list after completing the current Control or Bulk transaction that is in progress.

HCD (HC)

Bit fields structure

typedef union o_hcperiodicstart { struct { unsigned periodic_start : 14; unsigned unused0 : 18; } b; unsigned long w; } O_HcPeriodicStart