
dss-328
LP state
LP state
BLANKING_PERIOD
Video
HS
packet
Video
HS
packet
LP state
Video
HS
packet
LP state
LP state
enter
HS
exit HS
mode
Video
HS
packet
exit HS
mode
LP state
enter
HS
Period for interleaving
LP command mode
packets
Period for interleaving LP
command mode packets
Period for interleaving LP
command mode packets
Period for interleaving LP command mode packets
LP_INTERLEAVING
LP_INTERLEAVING
LP_INTERLEAVING
LP_INTERLEAVING
(1)
(2)
(3)
(4)
Public Version
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Display Subsystem Functional Description
Figure 7-92. LP Command Mode Interleaving
For the following equations, BLANKING_PERIOD represents the BLLP, HSA, HBP, or HFP blanking
periods. The LP_INTERLEAVING period represents the maximal period in LP command mode packets. Its
value is set in the BL_LP_INTERLEAVING, HSA_LP_INTERLEAVING, HBP_LP_INTERLEAVING, or
HFP_LP_INTERLEAVING registers, depending on the blanking type.
ALLOWED_HSBYTE_CLOCKS_FOR_LP represents the number of TxByteClkHS clock cycles during
which LP interleaving can appear.
To calculate the LP_INTERLEAVING value:
1. Calculate how many TxByteClkHS clock cycles can be reserved for LP interleaving during the
appropriate blanking video mode gap.
2. Calculate the LP_INTERLEAVING value according to the results of Step 1.
Step 1:
•
Scenario 1: The gap for interleaving starts and ends with a regular video stream HS packet.
ALLOWED_HSBYTE_CLOCKS_FOR_LP = BLANKING_PERIOD – (EXIT_HS_MODE_L
max{ ENTER_HS_MODE_LATENCY, 2} + 1)
•
Scenario 2: The gap for interleaving starts with a regular video stream HS packet and ends in LP state.
ALLOWED_HSBYTE_CLOCKS_FOR_LP = BLANKING_PERIOD – (EXIT_HS_MODE_L 1)
•
Scenario 3: The gap for interleaving starts with the LP state and ends with a regular video stream HS
packet.
1669
SWPU177N – December 2009 – Revised November 2010
Display Subsystem
Copyright © 2009–2010, Texas Instruments Incorporated