Altera CPRI IP Core - Manual (Page 173)

December 2013 Altera Corporation CPRI MegaCore Function
User Guide
D. Advanced AxC Mapping Modes
The advanced AxC mapping modes are implemented when map_mode has value 2’b01,
2’b10, or 2’b11 (and you specify All as the value for Mapping mode(s) in the CPRI
parameter editor), or if you specify Advanced 1, Advanced 2, or Advanced 3 as the
value for Mapping mode(s) in the CPRI parameter editor. In these 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.
1 Altera recommends that you use sample rates that are integer multiples of 3.84 MHz.
However, for implementing the WiMAX protocol, Altera recommends that you use
the exact WiMAX input sample rates. WiMAX applications require that your CPRI IP
core implement an advanced AxC mapping mode.
The CPRI IP core supports the following advanced AxC mapping modes:
■ When map_mode has the value of 2’b01 or 2’b11 (Advanced 1 or Advanced 3), AxC
mapping conforms to Method 1: IQ Sample Based, described in Section 4.2.7.2.5 of
the CPRI V4.2 Specification.
■ When map_mode has the value of 2’b10 (Advanced 2), AxC mapping conforms to
Method 3: Backward Compatible, described in Section 4.2.7.2.7 of the CPRI V4.2
Specification.
For a list of the standards supported by the various advanced mapping modes, refer
to
Table 3–2 on page 3–5 .
Backward Compability
The CPRI IP core supports one new advanced mapping mode in the Quartus II
software 11.1 and later releases. To support the new advanced mapping mode,
advanced mapping mode encodings changed in the Quartus II software 11.1 release.
Table D–1 shows the correspondence between the advanced mapping mode map_mode
encodings in the software 11.1 and later releases and the encodings in previous
software releases. The 2’b01 encoding has a different meaning in the software 11.1 and
later releases than in previous releases.
Table D–1. Advanced Mapping Mode map_mode Encodings in Software Releases
Mode
CPRI Parameter Editor
Mapping mode(s) Value
map_mode Encoding
In Quartus II Software
Releases 11.1 and Later
In Quartus II Software
Release
11.0 and Earlier
New implementation of
Method 1: IQ Sample Based
Advanced 1 2’b01 —
Conforms to Method 3:
Backward Compatible
Advanced 2 2’b10 2’b10
Conforms to Method 1:
IQ Sample Based
Advanced 3 2’b11 2’b01