Intel NETWORK PROCESSOR IXP2800 - Manual (Page 288)

288 Hardware Reference Manual
Intel
®
IXP2800 Network Processor
Media and Switch Fabric Interface
8.7.1.3 Single IXP2800 Network Processor
1. The Microengine or the Intel XScale ® core writes a 1 to MSF_Tx_Control[Transmit_Idle] and
MSF_Tx_Control[Transmit_Enable] so that Idle CFrames with low CReady and DReady bits
are sent over TDAT.
2. The Microengine or the Intel XScale
®
core writes a 1 to MSF_Rx_Control[RX_En_C] so that
Idle CFrames can be received.
3. The Microengine or the Intel XScale
®
core writes a 0 to
FC_STATUS_OVERRIDE[Ingress_Force_En].
4. The Microengine or the Intel XScale ® core polls on
MSF_Interrupt_Status[Detected_CSIX_Idle] to see when the first Idle CFrame is received.
The Intel XScale
®
core may use the Detected_CSIX_Idle Interrupt if
MSF_Interrupt_Enable[Detected_CSIX_Idle] is set.
5. When the first Idle CFrame is received, the Microengine or the Intel XScale ® core writes a 0
to FC_STATUS_OVERRIDE[Egress_Force_En] to deactivate SRB Override or writes 2'b11
to FC_STATUS_OVERRIDE[7:6] ([TM_CReady and TM_DReady]).
6. The Microengine or the Intel XScale ® core writes a 1 to MSF_Tx_Control[TX_En_CC] and
MSF_Tx_Control[TX_En_CD]. IXP2800 resumes normal operation.
8.7.2 CSIX Simplex
8.7.2.1 Ingress IXP2800 Network Processor
1. On reset, FC_STATUS_OVERRIDE[Egress_Force_En] is set to force Ingress IXP2800 to
send Idle CFrames with low CReady and DReady bits to Switch Fabric over TXCDAT.
2. The Microengine or the Intel XScale
®
core writes a 1 to MSF_Rx_Control[RX_En_C] so that
Idle CFrames can be received.
3. The Microengine or the Intel XScale ® core polls on
MSF_Interrupt_Status[Detected_CSIX_Idle] to see when the first Idle CFrame is received.
The Intel XScale
®
core may use the Detected_CSIX_Idle Interrupt if
MSF_Interrupt_Enable[Detected_CSIX_Idle] is set.
4. When the first Idle CFrame is received, the Microengine or the Intel XScale ® core writes a 0
to FC_STATUS_OVERRIDE[Egress_Force_En]. Idle CFrames with “ready bits” high will be
transmitted over TXCDAT. Ingress IXP2800 may resume normal operation.