SN65DSI86: What is the maximum resolution supported by sn65dsi86

Hi,

Please see this app note, https://www.ti.com/lit/an/slla425/slla425.pdf, in particular section 3 for the calculation. You have to calculate the stream bit rate, and from the stream bit rate, depending on the number of DSI lanes being used, you can't exceed the maximum 750MHz DSI clock.

Do you know the pixel clock frequency for this particular resolution?

Thanks

David

Hi David,

1.Panel Parameters:

refresh rate:60Hz

Display Width:2880
Display Height:1800

Hsync Pulse Width:32
Hori. Back Porch:40
Hori. Back Porch + hsync pulse width:72
Hori. Front Porch:8

Vsync Pulse Width:8
Vert. Back Porch:64
Vert. Back Porch + VSync pulse width:72
Vert. Front Porch:8

Escclk source:27MHz

2.Because we use dual DSI(the single DSI:Display Width=1440),  the single DSI is calculated as follows:

bitclk (desired frequency):1028.74MHz
byteclk (actual frequency):128.59MHz
dsiclk (actual frequency):514.37MHz
pclk (actual frequency):171.46MHz

3.We will use a dual DSI, dose sn65dsi86 support this Panel? What is the eDP frequency?

4.Is The maximum 750MHz DSI clock single DSI, or the sum of dual DSI?

Hi,

With PCLK of 171.46MHz, and 24bpp, the stream bit rate is 171.46x24= 4.11504, 

DSI CLK frequency = 4.11504 / (2 x DSI lane). If using DSI lane of 4, DSI CLK = 514.38MHz, so you don't need dual DSI, single DSI will work for this application. 

Thanks

David

Hi David,

DSI CLK = 514.38MHz indicates dual dsi mode with left and right split screens. The Display Width is 1440.

The panel resolution is 2880*1800. For a single dsi, Display Width=2880, DSI CLK = 1001.66MHz, more than 750MHz.

If it's a left/right split screen, <DSI Tuner> tools warns The Display Width less than 1400, so if we are using dual dsi, left/right split screen, can we support this panel?

Hi,

DSI86 can support dual-channel DSI odd, even and left, right operating modes.

Thanks

David

How to calculate DP data rate?

Why is the prompt HActive less than 1408?
Is it the wrong way to use the tool?
Will you get an error using this parameter?

Hi,

Please do not use the DSI Tuner SW for DSI86, you can use this spreadsheet to generate the DSI86 registers programming values. 

https://e2e.ti.com/support/interface-group/interface/f/interface-forum/945404/faq-sn65dsi86-how-do-i-programming-the-sn65dsi86-registers

Thanks

David

Hi，

In LR mode, is the value of DSI_HActive Channel A&B greater than 1408? Can it be greater than 1408?
OE mode does not have this warning. Is there any error in my parameter filling?

Thanks

Hi,

Can you share your spreadsheet? DSI_CHA/B_HACTIVE_LENGTH_HIGH and LOW should be 1440.

Thanks

David

Hi,

frame rate 60
lane config 4
pixel format BPP 3

Active Width 2880
Active Height 1800

Hsync Pulse Width 32
Hori. Back Porch 40
Hori. Front Porch 8

Vsync Pulse Width 8
Vert. Back Porch 64
Vert. Front Porch 8

Escclk source (MHz) 27

DPHY

We need to use Dual Dsi mode, why does tuner tools tell me "DSI HActive Channel A value should be less than 1408"? Just like the screenshot.

Is there any problem with 1440?

Thanks!

Hi,

Please do not use the DSI Tuner SW for DSI86, you can use this spreadsheet to generate the DSI86 registers programming values. 

https://e2e.ti.com/support/interface-group/interface/f/interface-forum/945404/faq-sn65dsi86-how-do-i-programming-the-sn65dsi86-registers

Thanks

David

Hi David,

I use DSI Tuner tools to make the screen work properly. Using this spreadsheet causes the screen to not work properly.
Fill in the C14 of spreadsheet "Vertical Blanking (lines)=37" and calculate 0x36 as 0x0B, which is wrong, correct should be 0x25, and DSI Tuner calculated it as 0x25, which is correct.
Can you help me generate Qualcomm_ASSR code to compare the differences between our codes

Thanks!

Hi,

You can click on this button, and it will generate the Qualcomm ASSR text file Window Documents folder.

Thanks

David

Hi David,

I have solved this problem, thanks for your support!

Hi David,

I want to confirm with you whether sn65dsi86 can support the panel of 2.8K?
The following are the parameters, please help to confirm, thank you!

refresh rate:60Hz

Display Width:2880
Display Height:1800

Hsync Pulse Width:32
Hori. Back Porch:40
Hori. Back Porch + hsync pulse width:72
Hori. Front Porch:8

Vsync Pulse Width:8
Vert. Back Porch:64
Vert. Back Porch + VSync pulse width:72
Vert. Front Porch:8

Escclk source:27MHz