Intel E3815 FH8065301567411 Data Sheet

 

Intel

®

 Atom™ Processor E3800 Product Family

Datasheet

2503

The Doorbell Array is organized as an array of up to 256 Doorbell Registers. One 32-bit 

Doorbell Register is defined in the array for each Device Slot. System software utilizes 

the Doorbell Register to notify the xHC that it has Device Slot related work for the xHC 

to perform.

Default: 00000000h

7:0

0h

RW

DB Target RW. Doorbell Target. This field defines the target of the 

doorbell reference. The table below defines the xHC notification that is generated by 

ringing the doorbell. Note that Doorbell Register 0 is dedicated to Command Ring and 

decodes this field differently than the other Doorbell Registers. Device Context Doorbells 

(1-255) for Value 0 the Definition is Reserved for Value 1 the Definition is Control EP 0 

Enqueue Pointer Update for Value 2 the Definition is EP 1 OUT Enqueue Pointer Update 

for Value 3 the Definition is EP 1 IN Enqueue Pointer Update for Value 4 the Definition is 

EP 2 OUT Enqueue Pointer Update for Value 5 the Definition is EP 2 IN Enqueue Pointer 

Update . . . for Value 30 the Definition is EP 15 OUT Enqueue Pointer Update for Value 

31 the Definition is EP 15 IN Enqueue Pointer Update for Value 32:247 the Definition is 

Reserved for Value 248:255 the Definition is Vendor Defined Host Controller Doorbell (0) 

for Value 0 the Definition is Command Doorbell for Value 1:247 the Definition is 

Reserved for Value 248:255 the Definition is Vendor Defined This field returns 0 when 

read and should be treated as undefined by software. When the Command Doorbell is 

written, the DB Stream ID field shall be cleared to 0.

Memory Mapped I/O Register

(Size: 32 bits)

PCI Configuration Register (Size: 32 bits)

[B:0, D:22, F:0] + 10h

31

28

24

20

16

12

8

4

0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

DB

_

S

TREA

M_ID

RSV

D

33

DB_T

ARGET

31:16

0h

RW

DB Stream ID - RW. Doorbell Stream ID. If the endpoint of a Device 

Context Doorbell defines Streams, then this field shall be used to identify which Stream 

of the endpoint the doorbell reference is targeting. System software is responsible for 

ensuring that the value written to this field is valid. If the endpoint defines Streams 

(MaxPStreams ) 0), then 0, 65535 (No Stream) and 65534 (Prime) are reserved Stream 

ID values and shall not be written to this field. If the endpoint does not define Streams 

(MaxPStreams = 0) and a non-'0' value is written to this field, the doorbell reference 

shall be ignored. This field only applies to Device Context Doorbells and shall be cleared 

to 0 for Host Controller Command Doorbells. This field returns 0 when read.

15:8

0h

RO

reserved