Altera CPRI IP Core - Manual (Page 56)

4–24 Chapter 4: Functional Description
MAP Interface
CPRI MegaCore Function December 2013 Altera Corporation
User Guide
■ In the CPRI_MAP_OFFSET_RX register, the cpri_rx_offset_z field has the value of 3
and the cpri_rx_offset_x field has the value of 4.
In Figure 4–12 , the map0_rx_start signal pulses synchronously with the first rising
edge of map0_rx_valid following the CPRI frame offset specified in the
CPRI_MAP_OFFSET_RX register. The mapN_rx_valid signals are asserted in round-robin
order, following the basic mapping mode.
The internally-clocked mode is useful only with the basic mapping mode. The
advantage of the advanced mapping modes is their support for different clocks on
different antenna-carrier interfaces, a feature not available with the internally-clocked
synchronization mode.
MAP Transmitter Interface
The MAP transmitter interface receives data from the data channels and passes it to
the CPRI protocol interface to transmit on the CPRI link. The MAP transmitter
implements an Avalon-ST interface protocol. Refer to
“MAP Transmitter Signals” on
page 6–3 for details of the interface communication signals.
Figure 4–12. MAP Receiver Interface in the internally-Clocked Mode
cpri_clkout
cpri_rx_hfn
cpri_rx_x
map0_rx_start
map0_rx_valid
map0_rx_data[31:0]
map1_rx_start
map1_rx_valid
map1_rx_data[31:0]
map2_rx_start
map2_rx_valid
map2_rx_data[31:0]
3
3 4 5 6