
3–16 Chapter 3: Functional Description
Block Description
Serial Digital Interface (SDI) MegaCore Function February 2013 Altera Corporation
User Guide
Figure 3–9 shows the receiver clocks for different video standards.
Transmitter Transceiver Interface
Altera provides a transceiver interface, which interfaces the transceiver to the SDI
function. The transceiver interface implements the following functions:
■ Transmitter Retiming
■ HD-SDI Two-Times Oversampling
■ SD-SDI Transmitter Oversampling
1 When using the two-times oversampling transmitters in Stratix GX devices, you
cannot have HD-SDI receivers in the same quad. The quad requires the same
frequency reference clocks for both the receivers and transmitters within a quad.
HD-SDI receivers and two-times oversampling transmitters have different frequency
reference clocks (refer to Table 3–5 and Table 3–6 on page 3–15).
Transmitter Retiming
The
txdata
parallel data input to the transceiver must be synchronous and phase
aligned to the
tx_coreclk
transceiver clock input. SD-SDI (and optionally HD-SDI)
requires a retiming function, because of the oversampling logic. The transmitter uses a
small 16 × 20 FIFO buffer for the retiming.
Figure 3–9. Receiver Clocks
rx_clk
rx_data
rx_data_valid_out
V VVV
SDI MegaCore
Function
74.25/74.175 MHz
Serial Data
HD-SDI
rx_clk = 74.25 MHz
rx_data_valid_out
rx_clk
rx_data
rx_data_valid_out
V VV V
SDI MegaCore
Function
67.5 MHz
Serial Data
SD-SDI
rx_clk = 67.5 MHz
rx_data_valid_out
SDI MegaCore
Function
67.5 MHz
Serial Data
Dual Standard
rx_clk = 67.5 or 74 MHz
rx_data_valid_out
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