The management interface is implemented as a generic, processor-friendly, memory-mapped register block that enables easy connection to either an internal processor (such as the MicroBlaze™ soft processor) or to an off-chip processor.
The management interface signals are described in Table: Management Interface Signals , and the timing is illustrated in This Figure and This Figure .
Note: The mgmnt_req signal must be deasserted for at least one clock cycle between accesses; back-to-back transactions are not permitted.
|
Port |
Direction |
Clock Domain |
Description |
|---|---|---|---|
|
mgmnt_addr |
In |
Management Clock |
Management Address Bus. See Management Register Map for address definitions. This port is 8 bits wide when 24,330.24 Mb/s operation is supported,5 bits wide when 4,915.2, 6,144.0, 9,830.4, 10,137.6, or 12,165.12 Mb/s operation is supported and 4 bits wide otherwise. |
|
mgmnt_req |
In |
Management Clock |
Management Request |
|
mgmnt_rnw |
In |
Management Clock |
Management Read/Not Write
When 1, read from management block
|
|
mgmnt_wr_data[31:0] |
In |
Management Clock |
Management Write Data |
|
mgmnt_ack |
Out |
Management Clock |
Management Acknowledge |
|
mgmnt_rd_data[31:0] |
Out |
Management Clock |
Management Read Data |
|
l1_timer_expired |
In |
Management Clock |
L1 Timer Expired flag |
|
The core provides an input port, l1_timer_expired , to allow the connection of a Layer 1 Timer (not supplied with core). According to Clause 4.5.2 of the CPRI specification, this timer should be started upon entry of the start-up procedure and cleared when the C&M channel is established (that is, when bit 3 of stat_code is set; see Status and Alarm Interfaces .)
When the l1_timer_expired input is set to 1, the start-up state machine in the CPRI core returns to State B, “Attempting L1 Synchronization” (shown as transition 16 in the CPRI specification) and the stat_code output becomes 0001. The l1_timer_expired input should then be set to 0 to allow the start-up procedure to restart.
If a level 1 timer is not implemented in the user logic then the l1_timer_expired port should be tied Low to allow the start-up procedure to complete.