DLPU115 January 2022 DLPC3421
Figure 3-3 describes the command parameters.
MSB | Byte 1 | LSB | |||||
---|---|---|---|---|---|---|---|
b7 | b6 | b5 | b4 | b3 | b2 | b1 | b0 |
b(7:2) | Reserved |
b(1:0) | Input Source:
|
When selecting the external video port, there is a set of associated commands applicable only to this source selection. These associated commands are the Write External Input image Size and the Write External Video Source Format Select.
When selecting the test pattern generator (TPG), only one associated command is applicable to this source selection. This associated command is the Write Test Pattern Select command.
When selecting the splash screen, only two associated commands are applicable to this source selection. These associated commands are the Write Splash Screen Select and Write splash Screen Execute commands.
These associations are also shown in Table 3-1.
Source Specific Associated Commands | Input Source Select Options | ||
---|---|---|---|
External Video Port | Test Pattern Generator | Splash Screen(1) | |
Write External Video Source Format Select | Only | N/A | N/A |
Write External Input Image Size | Only | N/A | N/A |
Write Test Pattern Select | N/A | Only | N/A |
Write Splash Screen Select | N/A | N/A | Only |
Write Splash Screen Execute | N/A | N/A | Special |
These commands (other than Write Splash Screen Execute) describe the characteristics of their associated source, and once these settings are defined the system stores them. Afterwards, each time an input source selection is made (using the Write Input Source Select command), the system remembers the settings described by the commands associated with the selected source, and automatically applies them. The user only needs to send these associated commands when the source is first defined, or when the source characteristics for that port have changed. The appropriate associated commands must be updated when source characteristics change.
The user can send source-associated commands every time they make an input source selection. The source associated commands must be sent prior to sending the Write Input Source Select command. When source-associated commands are sent when that source is not active, the controller software saves the new settings, but does not execute these commands. When that source becomes active (via the Write Input Source Select command), the controller applies these new settings, as in the following example:
If source-associated commands are sent for a source that is already active, the controller software executes these commands when received, as in the following example:
The rest of the commands that apply to image setup have settings applicable across all source selections, and typically remain the same across the three input source selections. A few examples are Write Display Size and Write Display Image Orientation. A representative list of these commands is shown in Table 3-2.
Common Commands | Input Source Select Options | ||
---|---|---|---|
External Video Port | Test Pattern Generator | Splash Screen | |
Write Image Crop | Common | Common | Common |
Write Keystone Correction Control | Common | Common | Common |
Write Display Image Orientation | Common | Common | Common |
Write Display Image Curtain | Common | Common | Common |
Write Look Select | Common | Common | Common |
Write Local Area Brightness Boost Control | Common | Common | Common |
Write CAIC Image Processing Control | Common | Common | Common |
The user is required to specify the active data size for all external input sources, using the Write Input Image Size command.
When a test pattern is selected, it is generated at the resolution of the DMD, modified by the settings specified by the Write Image Crop command, and displayed at the resolution specified by the Write Display Size command.
The user must see the Write Image Freeze command for information on hiding on-screen artifacts when selecting an input source.