Altera CPRI IP Core - Manual (Page 45)

Chapter 4: Functional Description 4–13
MAP Interface
December 2013 Altera Corporation CPRI MegaCore Function
User Guide
The CPRI IP core communicates with the RF implementations (antenna-carriers)
through multiple AxC interfaces, or data channels. A CPRI IP core configured with a
MAP interface module can have as many as 24 data channels, and as few as one data
channel. If a CPRI IP core is configured with zero data channels, it does not have a
MAP interface module. The Number of antenna/carrier interfaces value you set in
the parameter editor determines the number of channels in your CPRI IP core
configuration. Each data channel communicates with the corresponding RF
implementation using two 32-bit Avalon-ST interfaces, one interface for incoming
communication and one interface for outgoing communication.
The MAP interface module controls transmission and reception of data on the AxC
interfaces.
1 The MAP interface does not support GSM mapping. You must implement this CPRI
V5.0 Specification feature using the CPRI IP core AUX interface.
This section contains the following topics:
■ MAP Interface Mapping Modes
■ MAP Receiver Interface
■ MAP Transmitter Interface
MAP Interface Mapping Modes
The CPRI IP core supports basic and advanced MAP interface mapping modes.
In the basic mapping mode, all of the AxC interfaces use the same sample rate and
sample width, and the uplink and downlink sample rates are identical.
In the advanced mapping modes, different data channels can use different sample
rates, and the sample rates need not be integer multiples of 3.84 MHz. However, all
data channels use the same sample width.
If you select All as the value for Mapping mode(s) in the CPRI parameter editor, the
map_mode field of the CPRI_MAP_CONFIG register determines the mapping mode your
CPRI IP core implements currently. Otherwise, the value you specify for this
parameter determines the single mapping mode your CPRI IP core implements.
Table 4–4 lists the MAP interface mapping modes the CPRI IP core supports and how
to configure or program your IP core in each mapping mode.
Table 4–4. Determining the MAP Interface Mapping Mode (Part 1 of 2)
Mapping mode(s)
Parameter Value
Value Programmed in
map_mode field of
CPRI_MAP_CONFIG
Register
Mapping
Mode
Mode Description
Basic Don’t Care
Basic In current section
All 2’b00