OLDITX0 and OLDITX1 support:
- Single link output mode: This
is a single stream format for which up to four serial data lanes (four LVDS
pairs) are used to transmit a video stream. An additional lane is used to
transmit the pixelclock.
- 2x Single-link (duplication) output mode: This is a dual stream format for
which up to four serial data lanes are used to transmit each video stream (8
total). An additional lane is used to transmit each pixel clock.
- Dual link output mode: This
is a single stream format which up to eight serial data lanes are used to
transmit a video stream. An additional two lanes are used to transmit the
pixelclock.
A single OpenLDI interface is capable of driving
up to WUXGA (1920x1200@60p, 162 MHz pixel clock) resolution, and can be used as long
as the receiving display or link bridge device can accept the video output from the
device through a single OLDI link. Typically, only display resolutions less than
1366x768 require a single link interface. Adding the second interface for dual-link
operation does not increase available bandwidth, but decreases required pixel clock
by half.
The sequence of bringing up OLDITX in single link mode is as follows:
- Configure all PLLs that provide the required OLDITX clocks (see Module
Integration).
- Keep OLDITX_SW_RST in the default reset state 0 (controlled via
DSS0_VP_DSS_OLDI_CFG[12] SOFTRST register bit).
- Configure the following parameters:
- Input video data and pixel clock source, in DSS0_VP_DSS_OLDI_CFG[4]
SRC register bit
- OLDITX module enable, in DSS0_VP_DSS_OLDI_CFG[0] ENABLE register
bit
- DE input polarity, in DSS0_VP_DSS_OLDI_CFG[7] DEPOL register bit
- Combining of links,
in DSS0_VP_DSS_OLDI_CFG[11] DUALMODESYNC register bit:
- Zero for
single-link(s)
- One for
dual-link
- Link mode, in DSS0_VP_DSS_OLDI_CFG[5] MODE register bit:
- Zero for
single stream
- One for
stream duplication
- Mapping of video to LVDS channel (for single link mode), in
DSS0_VP_DSS_OLDI_CFG[3-1] MAP register field:
- A, B, or C
Types for single-link
- D, E, or F
Types for dual-link
- Input data format (for 18-bit LVDS output), in
DSS0_VP_DSS_OLDI_CFG[8] MSB register bit
- Test pattern enable (must be 0 for normal operation), in
DSS0_VP_DSS_OLDI_CFG[13] TPATCFG register bit
- Software checks that the PLLs are stable and locked.
- Release OLDITX_SW_RST = 1 (by configuring DSS0_VP_DSS_OLDI_CFG[12]
SOFTRST register bit).
- Software waits for DSS0_COMMON_DSS_SYSSTATUS[5] OLDI_RESETDONE
register bit = 1.
- DSS sends RGB data.
Typically, OLDITX should be configured to send out
24-bit RGB data on four LVDS data lanes. But, it can also be configured (via
DSS0_VP_DSS_OLDI_CFG[3-1] MAP register field) to send only 18-bit RGB
data (6-bits/component) on three LVDS lanes, when connecting to a low resolution
monitor. In this configuration, only 4 LVDS pairs (3 data lanes + 1 clock lane) are
active, while the 4th data lane is disabled. When OLDITX is configured to send out
18-bit LVDS-mapped data, then the DSS0_VP_DSS_OLDI_CFG[8] MSB register bit
must be used to select the format of the input source data bus (for more
information, see Section 12.9.1.4.2.4, OLDITX Input Interface).
Note: Software may change the mode of operation by first
asserting low the OLDITX_SW_RST reset, then follow the sequence described in
this section.
Software needs to ensure that OLDITX_SW_RST is
asserted low, if the PLLs are not locked.
For more information on LVDS data format mapping and LVDS data output bit format, see Section 12.9.1.2.2, DSS LVDS Interface.