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Hardware Reference Manual 281
Intel
®
IXP2800 Network Processor
Media and Switch Fabric Interface
The IXP2800 Network Processor supports all three methods. There are three groups of high-speed
pins to which this applies, as shown in Table 104, Table 105, and Table 106. The groups are
defined by the clock signal that is used.
Table 104. Data Deskew Functions
Clock Signals IXP2800 Network Processor Operation
RCLK
RDAT 1. Sample point for each pin is programmed in Rx_Deskew.
2. Deskew values set automatically when training pattern (Section 8.6.1) is
received and is enabled in Train_Data[Ignore_Training].
RCTL
RPAR
RPROT
TCLK
TDAT 1. Send training pattern
• under software control (write to Train_Data[Continuous_Train] or
Train_Data[Single_Train])
• when TSTAT input has framing pattern for more than 32 cycles and enabled in
Train_Data[Train_Enable].
TCTL
TPAR
TPROT
Table 105. Calendar Deskew Functions
Clock Signals IXP2800 Network Processor Operation
RSCLK RSTAT
1. Used to indicate need for data training on receive pins by forcing to continual
framing pattern (write to Train_Data[RSTAT_En]).
2. Send training pattern under software control (write to
Train_Calendar[Continuous_Train] or Train_Calendar[Single_Train]).
TSCLK TSTAT
1. Sample point for each pin is set in Rx_Deskew, either by manual programming
or automatically.
2. Deskew values set automatically when training pattern (Section ) is received
and is enabled in Train_Calendar[Ignore_Training].
3. Received continuous framing pattern can be used to initiate data training
(Train_Data[Detect_No_Calendar]), and/or interrupt the Intel XScale
®
core.
Table 106. Flow Control Deskew Functions
Clock Signals IXP2800 Network Processor Operation
RXCCLK
RXCSOF 1. Sample point for each pin is programmed in Rx_Deskew.
2. Deskew values set automatically when training pattern (Section 8.6.2) is
received and is enabled in Train_Flow_Control[Ignore_Training].
Note 1, 2
RXCDAT
RXCPAR
RXCSRB
TXCCLK
TXCSOF 1. Send training pattern
• under software control (write to Train_Flow_Control[Continuous_Train] or
Train_Flow_Control[Single_Train])
• when TXCFC input has been asserted for more than 32 cycles and enabled in
Train_Flow_Control[Train_Enable].
Notes 1, 2
TXCDAT
TXCPAR
TXCSRB
NOTES:
1. TXCFC is not trained. RXCFC is driven out relative to RXCCLK; TXCFC is received relative to TXCCLK,
but is treated as asynchronous.
2. RXCFC can be forced asserted by write to Train_Flow_Control[RXCFC_En].