Altera CPRI IP Core - Manual (Page 125)

Chapter 7: Software Interface 7–9
CPRI Protocol Interface Registers
December 2013 Altera Corporation CPRI MegaCore Function
User Guide
rx_slow_cm_rate [10:8] RO
Accepted receive slow C&M rate, as determined during
the software set-up sequence, or by dynamic
modification, in which the same new pointer value is
received in incoming CPRI control byte Z.66.0 four
hyperframes in a row.
The following values are defined:
000: No HDLC channel.
001: 240 Kbps
010: 480 Kbps
011: 960 Kbps
100: 1920 Kbps
101: 2400 Kbps
110: 3840, 4800, or 7680 Kbps, depending on the
current CPRI line rate, as specified in
Table 4–15 on
page 4–51 .
For information about compatible slow C&M rates and
CPRI line rates, refer to
Table 4–15 on page 4–51 .
3’h0
RSRV [7] UR0 Reserved. 1'h0
rx_fast_cm_ptr_valid [6] RO Indicates that a valid fast C&M pointer has been accepted. 1'h0
rx_fast_cm_ptr [5:0] RO
Accepted receive fast C&M pointer, as determined during
the software set-up sequence or by dynamic
modification, in which the same new pointer value is
received in incoming CPRI control byte Z.194.0 four
hyperframes in a row. The value is between 0x24 and
0x3F, inclusive.
6’h0
Table 7–15. CPRI_CM_STATUS—CPRI Control and Management Status—Offset: 0x2C (Part 2 of 2)
Field Bits Access Function Default
Table 7–16. CPRI_RX_DELAY_CTRL—Receiver Delay Control—Offset: 0x30
Field Bits Access Function Default
RSRV [31:17] UR0 Reserved. 15'h0
rx_buf_resync [16] RW
Force CPRI receiver buffer (Rx elastic
buffer) realignment. Altera recommends
that you resynchronize the Rx elastic
buffer after a dynamic CPRI line rate
change. Resynchronizing might lead to
data loss or corruption.
1’h0
RSRV [15:WIDTH_RX_BUF] (1) UR0 Reserved. 0
rx_buf_int_delay [(WIDTH_RX_BUF-1):0] (1) RW
Initial buffer delay with which to align the
Rx elastic buffer. After you modify the
value of this field, you must set the
rx_buf_resync bit to resynchronize the
buffer.
2 WIDTH_RX_BUF-1
Note to Table 7–16 :
(1) WIDTH_RX_BUF is the value specified for the Receiver buffer depth parameter. This value is log
2
of the depth of the Rx elastic buffer. By default,
it is set to six, specifying a 64-entry buffer. Altera recommends that you set it to four, specifying a 16-entry buffer, in slave configurations.