Altera DisplayPort MegaCore Function - Manual (Page 31)

The
txN_ss
interface input data format corresponds to four, 15-nibble code words as specified by the
DisplayPort version 1.2a specification section 2.2.6.3. The upstream Reed-Solomon encoder supplies these
15-nibble code words. The format differs for header and payload as shown in the following figure.
Figure 4-7: Secondary Stream Input Data Format
0
nb0
nb1
nb2
nb3
0
0
0
0
nb4
nb5
nb6
nb7
p0
p1
0
0
0
0
0
0
0
0
0
0
0
nb0
nb1
p0
p1
15-Nibble Code Word
for Packet Payload
15-Nibble Code Word
for Packet Header
The following figure shows a typical secondary stream packet with a four-byte header (HB0, HB1, HB2
and HB3) and a 32-byte payload (DB0 … DB31). The core calculates the associated parity bytes. The
secondary stream interface uses the start-of-packet (SOP) and end-of-packet (EOP) to determine if the
current input is a header or payload.
Payloads that only contain the first 16 bytes can assert the EOP on the second cycle to terminate the
packet sequence. Data is clocked in to the secondary stream interface through the
tx_ss_clk
. This clock
is the same phase and frequency as the main-link lane 0 clock.
UG-01131
2015.05.04
Secondary Stream Interface 4-15
DisplayPort Source Altera Corporation
Send Feedback