BCM1250/BCM1125/BCM1125H
User Manual
10/21/02
B r o a d c o m C o r p o r a t i o n
Page
250
Section 8: PCI Bus and HyperTransport Fabric
Document
1250_1125-UM100CB-R
7
XmitOff
R/S 1’b0
This bit can be set by the software to shut off a transmitter. When set none of the
output pins will toggle. If the EOC bit is set on an active link XmitOff should not be
set until the transmitter has driven enough NOP packets to fill the receiver’s receive
FIFOs. Once set this bit can only be cleared by a fabric reset.
11:8
CrcErr
R/C 4’b0
When a CRC error is received on the incoming link the bridge will set the bit in this
field corresponding to the byte lane that had the error. The BCM1250 only supports
an 8-bit link, so bit [8] is the only one that will ever be set.
Software may clear these bits by writing a 1 to them.
15:12
reserved
R/O 4’b0
Reserved
Table 146: HyperTransport Link Control Register - Offset 44 Bits [15:0]
(Cont.)
Bits
Name
Default
Description
Table 147: HyperTransport Link Configuration Register - Offset 44 Bits [31:16]
Bits
Name
Default
Description
Note that this register matches the HyperTransport 1.0 standard, and is a superset of rev 0.17
2:0
MaxIn
R/O 3’b000
This field indicates the BCM1250 only supports an 8 bit input link.
3
DwFcIn
R/O 1’b0
The bridge is not capable of Doubleword Flow Control.
6:4
MaxOut
R/O 3’b000
This field indicates the BCM1250 only supports an 8 bit output link.
7
DwFcOut
R/O 1’b0
The bridge is not capable of Doubleword Flow Control.
10:8
WidthIn
R/O 3’b000
This field is fixed for an 8 bit link.
11
DwFcInEn
R/O 1’b0
The bridge is not capable of Doubleword Flow Control.
14:12
WidthOut
R/O 3’b000
This field is fixed for an 8 bit link.
15
DwFcOutEn
R/O 1’b0
The bridge is not capable of Doubleword Flow Control.
Table 148: HyperTransport Link Frequency Register - Offset 48 Bits [15:8]
Bits
Name
Default
Description
3:0
LinkFreq
R/W
4’b0000
This register sets the maximum transmitter clock frequency for the link. The BCM1250
uses this value to control the PLL that provides both transmit and receive internal
clocks using the CLK100 reference. If the sriLinkFreqDirect bit is clear in the sriCmd
register, these bits have the encoding given in the HyperTransport 1.0 standard:
0000: 200 MHz (CLK100 x2)
0001: 300 MHz (CLK100 x3)
0010: 400 MHz (CLK100 x4)
0011: 500 MHz (CLK100 x5)
0100: 600 MHz (CLK100 x6)
0101: Not supported (code for 800 MHz)
0110: Not supported (code for 1000 MHz)
Others: UNDEFINED
4
LinkFreq
R/W 1’b0
If the sriLinkFreqDIrect bit is set in the sriCmd register then the [4:0] field is used to
set the PLL frequency directly, using the values shown in
. The link
frequency will be set to CLK100 * LinkFreq[4:0]/2.
The HyperTransport link clock frequency must not be set faster than four times the
frequency of the I/O bridge 0 clock. If the bridge is set (using the configuration resistor
on IO_AD[5]) to CPU clock/4 then the HyperTransport clock frequency must be less
than or equal to the CPU clock frequency. If the bridge is set to CPU clock/3 then the
HyperTransport link clock must be run at less than or equal to 4/3 of the CPU clock
frequency.
Note that the sriLinkFreqDirect bit must be set before the frequency code is written to
this register for the alternate frequencies to be used.
7:5
Reserved
R/O 3’b0
Reserved
Содержание BCM1125
Страница 18: ...BCM1250 BCM1125 BCM1125H User Manual 10 21 02 Broadcom Corporation Page xviii Document 1250_1125 UM100CB R ...
Страница 28: ...BCM1250 BCM1125 BCM1125H User Manual 10 21 02 Broadcom Corporation Page xxviii Document 1250_1125 UM100CB R ...
Страница 515: ...BCM1250 BCM1125 BCM1125H User Manual 10 21 02 Broadcom Corporation Page vii Index Document 1250_1125 UM100CB R ...