CPRI Intel® FPGA IP User Guide

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ID 683595
Date 4/04/2022
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3.11. Direct L1 Control and Status Interface

If you turn on Enable direct Z.130.0 alarm bits access interface in the CPRI parameter editor, the direct L1 control and status interface is available. This interface provides direct access to the Z.130.0 alarm and reset signals (loss of frame (LOF), loss of signal (LOS), service access point (SAP) defect indication (SDI), remote alarm indication (RAI), and reset request or acknowledge) in the CPRI hyperframe.

If you connect the AUX interface of your RE slave IP core to a network switch or other routing layer rather than directly to the downstream RE master, or if you do not fully connect the AUX interface to the downstream RE master, you can use this Z.130.0 access interface to streamline the transfer of reset requests and SDI alarms across hops.

This interface has higher transmit priority than access through the CPRI IP core registers.

This interface has the following types of signals:
  • _local_ signals are output signals from the IP core about the state of this IP core, and also indicate the IP core asserts the relevant outgoing Z.130.0 bit in the next CPRI hyperframe according to the transmit priority of this interface.
  • _assert signals are input signals the application can use to request that the IP core assert the relevant outgoing Z.130.0 bit in the next CPRI hyperframe according to the transmit priority of this interface. You can also connect these signals in an RE master to the corresponding _req output signals of the upstream RE slave in a multi-hop configuration, to support efficient transfer of reset requests and SDI alarms to the IP core.
  • _remote signals are output signals from the IP core that indicate the IP core received a Z.130.0 byte on the CPRI link with the relevant bit asserted by the CPRI link partner.
  • _req signals are also output signals from the IP core that indicate the IP core received a Z.130.0 byte on the CPRI link with the relevant bit asserted by the CPRI link partner. However, these signals are intended to be passed downstream in a multi-hop configuration. If the IP core is an RE slave, and it connects to an RE master through the Z.130.0 alarm and reset interface in a multi-hop configuration, you can connect the RE slave IP core _req output signal directly to the corresponding _assert input signal on the downstream RE master for efficient communication of the reset request or SDI alarm.
Table 30.  Direct L1 Control and Status Interface Signals

All interface signals are clocked by the cpri_clkout clock.

Signal Name

Direction

Description

z130_local_lof Output Indicates the IP core has detected a local loss of frame. In this case, the state_l1_synch output signal indicates the L1 synchronization state machine is in state XACQ1 or XACQ2.

In this case the IP core also asserts the local_lof bit in the FLSAR register at offset 0x2C.

z130_local_los Output Indicates the IP core has detected a local loss of signal. The IP core asserts this flag if it detects excessive 8B/10B errors that trigger the assertion of the optional L1 debug rx_lcv output signal or the xcvr_los output signal and the rx_los field of the L1_CONFIG register.

In this case the IP core also asserts the local_los bit in the FLSAR register at offset 0x2C.

z130_sdi_assert Input Indicates that the master service access point (SAP) is not available. Possible causes for this situation are equipment error or that the connected slave IP core is forwarding an SDI request it detected to the current RE CPRI master IP core through a direct connection.
z130_local_rai Output Indicates that either the z130_local_lof or the z130_local_los signal is high; clears when both of those two signals are low. Logical OR of two output signals z130_local_lof and z130_local_los.

z130_reset_assert Input Reset request from the application or from an RE slave to the current RE CPRI master IP core through a direct connection.
z130_remote_lof Output Indicates LOF received in Z.130.0 control byte from remote CPRI link partner.

In this case the IP core also asserts the remote_lof bit in the FLSAR register at offset 0x2C.

z130_remote_los Output Indicates LOS received in Z.130.0 control byte from remote CPRI link partner.

In this case the IP core also asserts the remote_los bit in the FLSAR register at offset 0x2C.

z130_sdi_req Output Indicates remote SAP defect indication received in Z.130.0 control byte from remote CPRI link master. If the current CPRI IP core is an RE slave in a multi-hop configuration, you should connect this output signal directly to the z130_sdi_assert input signal of the downstream RE master.
z130_remote_rai Output Asserts when either z130_remote_lof or z130_remote_los is asserted, and clears when both z130_remote_lof and z130_remote_los have the value of 0.

In this case the IP core also asserts the rai_detected bit in the FLSAR register at offset 0x2C.

z130_reset_req Output If the current IP core is a CPRI link slave, indicates the IP core received a reset request in the Z.130.0 control byte from the remote CPRI link master.

If the current IP core is a CPRI link master, indicates the IP core received a reset acknowledgement in the Z.130.0 control byte from the remote CPRI link slave.

Figure 45. sdi_assert to sdi_req on Direct L1 Control and Status Interface


Figure 46. reset_assert to reset_req on Direct L1 Control and Status Interface


Figure 47. LOF, LOS, and RAI on Direct L1 Control and Status Interface


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