Altera CPRI IP Core - Manual (Page 88)

4–56 Chapter 4: Functional Description
CPRI Protocol Interface Layer (Physical Layer)
CPRI MegaCore Function December 2013 Altera Corporation
User Guide
Alarm Indications
The CPRI IP core can detect and report the following alarms:
■ Loss of signal (LOS)—the CPRI IP core reports this alarm in the rx_los field of the
CPRI_STATUS register at offset 0x4 ( Table 7–5 on page 7–3 ).
■ Loss of frame (LOF)—the CPRI IP core reports this alarm by resetting the rx_state
field of the CPRI_STATUS register at offset 0x4 ( Table 7–5 on page 7–3 ).
Your application detects the following alarms by reading the last received #Z.130.0
control byte in the
CPRI_RX_CTRL register:
■ Remote alarm indication (RAI)
■ Service access point (SAP) defect indication (SDI) errors
■ Reset requests received over the CPRI link
Figure 4–27. CPRI Frame Synchronization Machine (1)
Notes to Figure 4–27 :
(1) If the tx_prot_version field of the CPRI_TX_PROT_VER register ( Table 7–25 on page 7–12 ) holds the value 1, scrambling is not turned on. In this
case, the conditions when Y is in 2..5 are ignored.
(2) LOS=1 returns the state machine to the XACQ1 state. This transition has highest priority.
(3) Condition B is: Received byte not K28.5 when Y=W=X=0 or for some k in 2..5, received byte(unscrambled) not 0x50 when W=X=0 and Y=k.
XACQ1
XACQ2
XSYNC1
XSYNC2
HFNSYNC
W=X=0 and LOS=0 and
(Received K28.5 Byte when Y=0
and
Received Scrambled 0x50 Byte when Y=2..5)
W=X=0 and LOS=0 and
(Received K28.5 Byte when Y=0
and
Received Scrambled 0x50 Byte when Y=2..5)
W=X=0 and LOS=0 and
(Received K28.5 Byte when Y=0
and
Received Scrambled 0x50 Byte when Y=2..5)
Received K28.5 Byte/
Set Y:=W:=X:=0
W=X=0 and LOS=0 and
(Received K28.5 Byte when Y=0
and
Received Scrambled 0x50 Byte when Y=2..5)
LOS=1
B
B
B or
LOS=1
LOF=1
LOF=0
Power Up or Reset
B or
LOS=1
(2)
(2)
(3)
(3)
(3)
(3)
(2)