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Setting input resolution on Pico V2

WYA
Intellectual 2265 points

Dear developer,

If you are not clear about how to setup the input resolution for structured light applications, I hope this post helps.

The Pico V2 has the capability to accept different input resolutions (see programmer's guide I2C: x05).

Bit(s)

Description

Reset

Type

Notes

3:0

Select the input resolution:

x0 - QVGA portrait (240h*320v)

x1 - QVGA landscape (320h*240v)

x2 - HVGA portrait (320h*480v)

x3 - HVGA landscape (480h*320v)

x4 - VGA portrait (480h*640v)

x5 - VGA landscape (640h*480v)

x6 - NTSC landscape (720h*240v)

x7 - VGA landscape (640h*480v) cropped to HVGA (not scaled)

x8 - PAL/SECAM landscape (720h*288v)

x9 - RESERVED

xA+ - RESERVED

b001

wr

 

 

(1)

 

 

 

(1)

 

(2)

 15: 4

Spare

x000

 

 

31:16

Unused

 

 

 

When setting your input resolution to landscape (QVGA and VGA, including VGA cropped), be sure to also set the Aspect Ratio (see programmer's guide I2C: x0A).This command has no effect on all other settings. If the input resolution is set to VGA landscpe cropped but the Aspect Ratio is not set, you might see a strip on the right side of a solid color image or scrambled image when displaying a ramp. If this is the case, please check to see if your aspect ratio is set.

Bit(s)

Description

Reset

Type

0

QVGA/VGA Landscape Mode Aspect Ratio Modification:

0 – force 4:3 input aspect ratio source to fill 3:2 display

1 – preserve 4:3  aspect ratio of source

b0

w

 15: 1

Spare

x0000

 

31:16

Unused

 

 

VGA landscape mode is required for structured light applications to prevent unwanted scaling of patterns. In this mode, the chipset expects to see VGA landscape input frame, but the LEFT and TOP portions of VGA input image frame are ignored (cropped). This results in only the LOWER RIGHT hand 480x320 pixels being displayed.

 

 

  • 0
    Intellectual 590 points

    Hello,

     

    am I correct that for structured light applications x05 should set to x7 and x0A to 1?

     

    C.

  • 0 in reply to Curtis Newton
    TI__Intellectual 2265 points

    Curtis,

    I'm sorry I didn't mean to confuse you. If you are looking for a 1:1 mapping from the PC to the DMD, you want the input source to be set to VGA Landscape Cropped, and leave the aspect ratio to 3:2. If you set the aspect ratio (x0A) to 1, you are setting it to 4:3, which actually changes the image to scaled, and not cropped. But that does not seem to be what you are looking for.

     

     

  • 0 in reply to WYA
    Intellectual 590 points

    WYA,

     

    strange. I use a beagleboard and do this:

     

    root@beagleboard:~# /usr/bin/bus3-i2c 0x1b wb4 0x0A 0x00000001

    root@beagleboard:~# /usr/bin/bus3-i2c 0x1b wb4 0x05 0x00000007

     

    Whats happen is that my image is scaled. Its not cropped. I see this because I fill the framebuffer (framebuffer size is 640x480) with an image of 640x480. In this image only the left upper 480x320 are filled with some color, the other part is black. Now with 0x05 set to 0 the image fills the whole display. With set to 1 the image is scaled to the upper left corner of the projection.

    It seems that setting 0x0A to 1 also sets 0x05 to 5?!?!

    I do use a pico 2.

    Where is my error?

     

    C.

  • 0 in reply to Curtis Newton
    TI__Intellectual 2265 points

    Curtis,

    Have you tried swapping the 2 commands? It might be better to set the resolution first before scaling it.

     

  • 0 in reply to WYA
    Intellectual 590 points

    Hi,

     

    yes I did this. No effect. 

     

    Also I tested this:

     

    root@beagleboard:~# /usr/bin/bus3-i2c 0x1b wb4 0x0A 0x00000001

    root@beagleboard:~# /usr/bin/bus3-i2c 0x1b wb4 0x05 0x00000007

    root@beagleboard:~# /usr/bin/bus3-i2c 0x1b wb4 0x05 0x00000005

    root@beagleboard:~# /usr/bin/bus3-i2c 0x1b wb4 0x05 0x00000007

    root@beagleboard:~# /usr/bin/bus3-i2c 0x1b wb4 0x05 0x00000005

     

    What happens is that only the width of the projection is changing a little bit. But as long as 0x0A is not 0 I am not able to fill the whole display with a 480x320 image.

     

    C.

  • 0 in reply to Curtis Newton
    TI__Intellectual 2265 points

    Curtis,

    After re-reading your original message, what you described is actually the expected behavior. If you look at the app note online (http://www.ti.com/litv/pdf/dlpa021), on page 5, it shows what the "cropped" image should look like (figure 2) when the option x05=x00000007 is selected. The input is passed to the output unscaled. Full VGA is needed at the input, but only HVGA portion will be displayed.

     

  • 0 in reply to WYA
    Intellectual 590 points

    Hi,

     

    figure 2 shows what the input frame does look like. From an 640x480 image only the upper left 480x320 are taken and displayed with an 480x320 DMD. Otherwise it makes no sense. If the 480x320 input is scaled for projection with a 480x320 DMD there is no linear mapping between input and output. And why scaling? You can map them 1:1.

     

    C.

  • 0 in reply to Curtis Newton
    TI__Intellectual 2265 points

    Hi Curtis,

    The assumption for the case in the App note is that the input is VGA resolution from your PC. Therefore cropping/scaling is necessary depending on the "input resolution" mode selected. If you could input a HVGA resolution, then cropping or scaling would not be necessary.