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Display Subsystem Basic Programming Model
NOTE:
When the VC is used to send video mode data from the video port, the
[9] MODE_SPEED and the DSS.
[1] SOURCE bits are
ignored.
7.5.4.12.1 Video Mode Transfer
Description: One channel, video mode, no DMA requests, no bus turn-around.
1. Configure the display controller with the timing parameters.
2. Configure the DSS.
register as follows:
•
SOURCE bit is ignored by hardware
•
BTA_LONG_EN bit is set to 0: No BTA on long packet
•
BTA_SHORT_EN bit is set to 0: No BTA on short packet
•
MODE bit set to 1: The video mode is selected
•
MODE_SPEED bit is ignored by hardware
3. Configure the DSS.
to DSS.
registers.
4. Set the ForceTxStopMode bit to 1 in the DSS.
register.
5. Enable the channel by setting the DSS.
[0] VC_EN bit to 1
6. Enable the module by setting the DSS.
[0] IF_EN bit to 1.
7. Poll the ForceTxStopMode bit to 0 in the DSS.
register.
8. Enable the LCD video output by setting the DSS.
[0] LCDENABLE bit to 1
CAUTION
The restriction for stopping the video mode is that no frame must be sent by the
display controller (DISPC) after disabling video mode in DSI.
7.5.4.12.2 Command Mode Transfer Example 1
CAUTION
In DSI command mode, the display controller must be configured in stall mode
by setting the DSS.
[11] STALLMODE bit to 1.
Description: One channel, command mode, no DMA requests, manual bus turn-around
1. Configure the DSS.
register as follows:
•
SOURCE bit set to 0: The source is the L4 interconnect port
•
BTA_LONG_EN bit is set to 0: No automatic BTA on long packet
•
BTA_SHORT_EN bit is set to 0: No automatic BTA on short packet
•
MODE bit set to 0: The command mode is selected
2. Enable the packet sent interrupt by setting the DSS.
PACKET_SENT_IRQ_EN bit to 1
3. Set the ForceTxStopMode bit to 1 in the DSS.
register.
4. Enable the channel by setting the DSS.
[0] VC_EN bit to 1
5. Enable the module by setting the DSS.
[0] IF_EN bit to 1
6. Poll the ForceTxStopMode bit to 0 in the DSS.
register.
For long packet:
•
Write the header value into the DSS.
register
•
Write the data into the DSS.
register for the full payload.
Repeat step until WC is reached (see
)
For short packet:
•
Send short packets through the L4 interconnect: Write the header value into the
1749
SWPU177N – December 2009 – Revised November 2010
Display Subsystem
Copyright © 2009–2010, Texas Instruments Incorporated