307013-003 Datasheet, PDF (580/848 Pages) Intel Corporation – Intel I/O Controller Hub 7

EHCI Controller Registers (D29:F7)
13.2.3.2
Bit
Description
DATA_LEN_CNT — R/W. This field is used to indicate the size of the data to be
transferred.
default = 0h.
For write operations, this field is set by software to indicate to the hardware how many
bytes of data in Data Buffer are to be transferred to the console. A value of 0h
indicates that a zero-length packet should be sent. A value of 1–8 indicates 1–8 bytes
are to be transferred. Values 9–Fh are invalid and how hardware behaves if used is
3:0 undefined.
For read operations, this field is set by hardware to indicate to software how many
bytes in Data Buffer are valid in response to a read operation. A value of 0h indicates
that a zero length packet was returned and the state of Data Buffer is not defined. A
value of 1–8 indicates 1–8 bytes were received. Hardware is not allowed to return
values 9–Fh.
The transferring of data always starts with byte 0 in the data area and moves toward
byte 7 until the transfer size is reached.
NOTES:
1.
Software should do Read-Modify-Write operations to this register to preserve the contents
of bits not being modified. This include Reserved bits.
2.
To preserve the usage of RESERVED bits in the future, software should always write the
same value read from the bit until it is defined. Reserved bits will always return 0 when
read.
USBPID—USB PIDs Register
Offset:
MEM_BASE + A4h
Default Value: 0000h
Attribute:
Size:
R/W, RO
32 bits
This DWord register is used to communicate PID information between the USB debug
driver and the USB debug port. The debug port uses some of these fields to generate
USB packets, and uses other fields to return PID information to the USB debug driver.
Bit
31:24
23:16
15:8
7:0
Description
Reserved: These bits will return 0 when read. Writes will have no effect.
RECEIVED_PID_STS[23:16] — RO. Hardware updates this field with the received
PID for transactions in either direction. When the controller is writing data, this field is
updated with the handshake PID that is received from the device. When the host
controller is reading data, this field is updated with the data packet PID (if the device
sent data), or the handshake PID (if the device NAKs the request). This field is valid
when the hardware clears the GO_DONE#_CNT bit.
SEND_PID_CNT[15:8] — R/W. Hardware sends this PID to begin the data packet
when sending data to USB (i.e., WRITE_READ#_CNT is asserted). Software typically
sets this field to either DATA0 or DATA1 PID values.
TOKEN_PID_CNT[7:0] — R/W. Hardware sends this PID as the Token PID for each
USB transaction. Software typically sets this field to either IN, OUT, or SETUP PID
values.
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Intel ^® ICH7 Family Datasheet