SN65DSI84: CHA_SOT_BIT_ERR

alex lav

Part Number: SN65DSI84

Hi, I'm trying to write linux driver for SN65DSI84. I use this files as example.

DSI:
lanes = 4,
format = RGB888,
clock = 280 MHz

display-timings (from device tree):
timing0: timing0 {
    clock-frequency = <70000000>;
    hactive = <1024>;
    vactive = <768>;
    hback-porch = <160>;
    hfront-porch = <24>;
    vback-porch = <29>;
    vfront-porch = <3>;
    hsync-len = <136>;
    vsync-len = <6>;
    hsync-active = <0>;
    vsync-active = <0>;
    de-active = <0>;
    pixelclk-active = <0>;
};

I set DSI_CLK_DIVIDER to divide by 4 (LVDS clock = 70 MHz)

Test pattern work fine, but for real DSI signal I have an errors. Register 0xE5 bit2 and bit3 (CHA_SOT_BIT_ERR, CHA_LLP_ERR).

config.c sn65dsi84_i2c.h

over 5 years ago

0 alex lav over 5 years ago

Prodigy 50 points

I'm install DSI Tuner and config with it (CSR.txt). Now I see this (display.jpg).

LCD: G150XTN06

Errors remained (CHA_SOT_BIT_ERR, CHA_LLP_ERR).

6038.CSR.txt

0 JMMN over 5 years ago in reply to alex lav

TI__Guru 60870 points

Hello,

An engineer has been assigned, but response will be delayed due to holidays.

Regards,

JMMN

0 Ikechukwu Anyiam over 5 years ago

TI__Mastermind 35130 points

Hi Alex,

Please share the datasheet for your LCD. Please also share the .dsi file for your configuration from the DSI-Tuner (click the file icon in the top left corner of the tool and then click "Export File").

Regards,

I.K.

0 alex lav over 5 years ago in reply to Ikechukwu Anyiam

Prodigy 50 points

Hi! Here datasheet and .dsi files.

G150XTN06.1_rev1.0_GLY.pdf 2.zip

0 Ikechukwu Anyiam over 5 years ago in reply to alex lav

TI__Mastermind 35130 points

Hi Alex,

From comparing the settings in your .dsi file and the panel datasheet, I see two issues:

1. The mapping format is incorrect. You selected Format 1 in the DSI-Tuner, but your panel datasheet uses Format 2. You should select Format 2 in the DSI-Tuner.

2. You selected 280MHz as the DSI CLK frequency, which is too fast for the output LVDS CLK frequency and results in a line time mismatch. To calculate the DSI CLK frequency you need to use, you can use equation 2 in this application note: http://www.ti.com/lit/an/slla356/slla356.pdf

In your case, for a 70MHz LVDS CLK, your DSI CLK frequency should be 210MHz, and you can select 3 as the divisor value to generate the 70MHz LVDS CLK..

Please make these changes in the DSI-Tuner and then regenerate the CSR configuration text file. Please also make sure that you change the DSI CLK to 210MHz on your video processor.

Regards,

I.K.

0 Ikechukwu Anyiam over 5 years ago in reply to Ikechukwu Anyiam

TI__Mastermind 35130 points

Has this issue been resolved?

Regards,

I.K.

0 alex lav over 5 years ago in reply to Ikechukwu Anyiam

Prodigy 50 points

Hi I.K.
Errors disappeared when I change SoC DSI configuration (disabled LOW_POWER).
I did what you wrote above, and I have a black screen.
I think my problem is initialization sequence.
I don't control EN pin, it connected to capacitor.
Now I'm trying to do what you wrote here.

0 Ikechukwu Anyiam over 5 years ago in reply to alex lav

TI__Mastermind 35130 points

Hi Alex,

Understood. Please let me know if you need more support with the DSI84 configuration.

Regards,

I.K.

0 alex lav over 5 years ago in reply to Ikechukwu Anyiam

Prodigy 50 points

Hi I.K.

My problem is I don't disable dsi command mode in SoC.
Now it's work with my first setting (dsi clock=280, lvds clock=70, div=4, format1)

initialization sequence:

When I disconnect EN pin from SoC and reboot, display still working.
Is it necessary to set high EN pin during LP-11 state?

Next problem is lvds miss some frames.

But when I connect oscilloscope probe to one of dsi data pin, number of missed frames decreases.
Is it only hardware problem or I can fix with software?

0 Ikechukwu Anyiam over 5 years ago in reply to alex lav

TI__Mastermind 35130 points

Hi Alex,

The EN pin needs to stay high after it has been asserted.

If you are missing frames then it's likely you haven't configured the DSI84 correctly for your display. Please reference my earlier response detailing the errors with your configuration.

Regards,

I.K.

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SN65DSI84: CHA_SOT_BIT_ERR