32581C

Core Logic Module - USB Controller Registers - PCIUSB

Table 6-42. USB_BAR+Memory Offset: USB Controller Registers (Continued)

Bit

Description

Offset 34h-37h

HcFmInterval Register (R/W)

Reset Value = 00002EDFh

 

 

31

FrameIntervalToggle (Read Only). This bit is toggled by HCD when it loads a new value into FrameInterval.

 

 

30:16

FSLargestDataPacket (Read Only). This field specifies a value which is loaded into the Largest Data Packet Counter at

 

the beginning of each frame.

 

 

 

 

 

 

15:14

Reserved. Read/Write 0s.

 

 

 

 

13:0

FrameInterval. This field specifies the length of a frame as (bit times - 1). For 12,000 bit times in a frame, a value of 11,999

 

is stored here.

 

 

 

 

 

 

Offset 38h-3Bh

HcFrameRemaining Register (RO)

Reset Value = 00000000h

31FrameRemainingToggle (Read Only). Loaded with FrameIntervalToggle when FrameRemaining is loaded.

30:14 Reserved. Read 0s.

13:0

FrameRemaining (Read Only). When the HC is in the UsbOperational state, this 14-bit field decrements each 12 MHz

 

clock period. When the count reaches 0, (end of frame) the counter reloads with FrameInterval. In addition, the counter

 

loads when the HC transitions into UsbOperational.

 

 

 

 

Offset 3Ch-3Fh

HcFmNumber Register (RO)

Reset Value = 00000000h

 

 

 

 

31:16

Reserved. Read 0s.

 

 

 

 

15:0

FrameNumber (Read Only). This 16-bit incrementing counter field is incremented coincident with the loading of FrameR-

 

emaining. The count rolls over from FFFFh to 0h.

 

 

 

 

 

Offset 40h-43h

HcPeriodicStart Register (R/W)

Reset Value = 00000000h

 

 

 

 

31:14

Reserved. Read/Write 0s.

 

 

 

 

13:0

PeriodicStart. This field contains a value used by the List Processor to determine where in a frame the Periodic List pro-

 

cessing must begin.

 

 

 

 

 

 

Offset 44h-47h

HcLSThreshold Register (R/W)

Reset Value = 00000628h

 

 

 

 

31:12

Reserved. Read/Write 0s.

 

 

 

 

11:0

LSThreshold. This field contains a value used by the Frame Management block to determine whether or not a low speed

 

transaction can be started in the current frame.

 

 

 

 

 

Offset 48h-4Bh

HcRhDescriptorA Register (R/W)

Reset Value = 01000003h

 

 

31:24

PowerOnToPowerGoodTime. This field value is represented as the number of 2 ms intervals, ensuring that the power

 

switching is effective within 2 ms. Only bits [25:24] are implemented as R/W. The remaining bits are read only as 0. It is not

 

expected that these bits be written to anything other than 1h, but limited adjustment is provided. This field should be written

 

to support system implementation. This field should always be written to a non-zero value.

 

 

 

 

 

23:13

Reserved. Read/Write 0s.

 

 

12NoOverCurrentProtection. This bit should be written to support the external system port over-current implementation.

0:Over-current status is reported.

1:Over-current status is not reported.

11OverCurrentProtectionMode. This bit should be written 0 and is only valid when NoOverCurrentProtection is cleared.

0:Global Over-Current.

1:Individual Over-Current

10

DeviceType (Read Only). USB is not a compound device.

9NoPowerSwitching. This bit should be written to support the external system port power switching implementation.

0:Ports are power switched.

1:Ports are always powered on.

8PowerSwitchingMode. This bit is only valid when NoPowerSwitching is cleared. This bit should be written 0.

0:Global Switching.

1:Individual Switching

288

AMD Geode™ SC3200 Processor Data Book

Page 288
Image 288
AMD SC3200 Bit Description Offset 34h-37h, Offset 38h-3Bh, Reserved. Read 0s, Offset 40h-43h, Reset Value = 00000628h, 288