IP-CPRI Altera, IP-CPRI Datasheet - Page 22

• Manufacturer Part Number: IP-CPRI
• Description: IP CORE - Common Public Radio Interface (CPRI)
• Manufacturer: Altera

Specifications of IP-CPRI

• Software Application: IP CORE, Interface And Protocols, HIGH SPEED
• Supported Families: Arria II GX, Cyclone IV GX, HardCopy IV, Stratix IV
• Core Architecture: FPGA
• Core Sub-architecture: Arria, Cyclone, Stratix
• Rohs Compliant: NA
• Lead Free Status / RoHS Status: na
• Lead Free Status / RoHS Status: na

3–2
Number of Antenna-Carrier Interfaces
CPRI MegaCore Function User Guide
1
For a CPRI MegaCore function configured with slave clocking mode, the Slave
transmitter starting channel number and Slave receiver starting channel number do
the same. Both numbers must be starting channel numbers available in your design.
The two numbers must be different but the Quartus II software creates an FPGA
configuration with a single slave transceiver.
If you instantiate multiple CPRI MegaCore functions on the same device, you must
ensure each uses distinct transceiver channels.
The Number of antenna/carrier interfaces parameter specifies the number of
antenna-carrier interfaces, or data channels, in your CPRI MegaCore function. The
supported values are 0 to 24. Set this parameter to the maximum number of data
channels you expect your CPRI MegaCore function to use at the same time.
If you set this parameter to zero, your CPRI MegaCore function does not implement
the CPRI MAP interface. You might choose to use this option if your CPRI MegaCore
function passes IQ data samples through the AUX interface to an external custom
mapping function that you provide.
Software allows you to specify that some of the antenna-carrier interfaces that you
configure in your CPRI MegaCore function are not active. This feature allows you to
change the number of active and enabled data channels dynamically.
The combination of CPRI MegaCore function line rate, sampling width, and sampling
rate restricts the number of active antenna-carrier interfaces your CPRI MegaCore
function can support. For example, if your CPRI MegaCore function operates at line
rate 3.072 Gbps, it can support as many as 20 active antenna-carrier interfaces, but if
your CPRI MegaCore function operates at line rate 1.2288 Gbps, it can support a
maximum of eight active antenna-carrier interfaces. For details, refer to
Table 4–5 on page
The software configuration feature allows you to modify the number of active
antenna-carrier interfaces; if you modify this number, you must keep in mind the
restrictions for your current CPRI line rate. Otherwise, data is dropped in the
mapping to and from the individual antenna-carrier interfaces.
If you set the map_ac field of the CPRI_MAP_CNT_CONFIG register to a number N that is
lower than the value you specify for Number of antenna/carrier interfaces, then the
first N data channels are active and the others are not. In addition, for each
antenna-carrier interface you can use the relevant map_rx_enable bit of the
CPRI_IQ_RX_BUF_CONTROL register and the relevant map_tx_enable bit of the
CPRI_IQ_TX_BUF_CONTROL register to enable or disable the specific data channel and
direction. A data channel must be configured, active, and enabled to function. If it is
configured and active but not enabled, then data to and from it is ignored.
The value you specify for Number of antenna/carrier interfaces is referred to as
N_MAP in this user guide.
For more information about the antenna-carrier interfaces in a CPRI MegaCore
function, refer to
“CPRI MAP Interface Module” on page
4–26.
4–22.
Number of Antenna-Carrier Interfaces
December 2010 Altera Corporation
Chapter 3: Parameter Settings
Table 4–4
and