i.MX6 solo output BT.656 issue (MCIMX6S5EVM10AB)

[darrenwang]

Hi Qiang Li:
sorry for bother you.
I have a issue same as below case 1,
we use i.mx6 bt.656 (d0~ d7) + CLK output to tw8836 (d0 ~ d7) CLK,
no swap pin.issue screen:
when we output white line to display , and the line will Flashing.
we want to send 720*480@60hzNTSC(480i) resolution.The Techwell vendor said , imx6 sent twice EAV , not send SAV + EAV.(1)Does the driver setting incorrect?(2)HW how to vertify the waveform by scope?
where can i get the sample waveform for reference?
thank you so much.darren_wang@compal.com i.MX6 bt656 display interface"1, Using no external HSYNC/VSYNC, just with BT656 itself . iMX6S can not send correct BT656 signal to AK8817
source like bellow"
But here I have a problem about the patch into iMX6S customer board with AK8817 encoder chip.
1, Using no external HSYNC/VSYNC, just with BT656 itself . iMX6S can not send correct BT656 signal to AK8817
source like bellow
//-----------------------------------------------------------------------------------
/driver/video/mxc/mxc_bt656if.c
static struct fb_videomode bt656if_modedb[] = {
    {
     /* NTSC Interlaced output */
     "BT656-NTSC", 60, 720, 480, 37037,
     19, 3,
     20, 3,
     276, 1,
     FB_SYNC_HOR_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT,
     FB_VMODE_INTERLACED,
     FB_MODE_IS_DETAILED,},
    ......
    ......
};
//------------------------------------------------------------------------------------
/drivers/mxc/ipu3/ipu_disp.c
/* COUNTER_2: HSYNC for each line */
/* COUNTER_2: HSYNC for each line */
_ipu_di_sync_config(ipu,
        disp,         /* display */
        DI_BT656_SYNC_HSYNC,         /* counter */
        h_total - 1,     /* run count */
        DI_SYNC_CLK,    /* run_resolution */
        0,         /* offset */
        DI_SYNC_NONE,     /* offset resolution */
        0,         /* repeat count */
        DI_SYNC_NONE,     /* CNT_CLR_SEL */
        0,         /* CNT_POLARITY_GEN_EN */
        DI_SYNC_NONE,     /* CNT_POLARITY_CLR_SEL */
        DI_SYNC_NONE,     /* CNT_POLARITY_TRIGGER_SEL */
        0,         /* COUNT UP */
        2*div        /* COUNT DOWN */
        );

/* COUNTER_3: internal VSYNC for each frame */
_ipu_di_sync_config(ipu,
        disp,         /* display */
        DI_BT656_SYNC_IVSYNC,         /* counter */
        v_total - 1,     /* run count */
        DI_BT656_SYNC_HSYNC,    /* run_resolution */
        0,             /* offset */
        DI_SYNC_NONE,     /* offset resolution */
        0,         /* repeat count */
        DI_SYNC_NONE,     /* CNT_CLR_SEL */
        0,         /* CNT_POLARITY_GEN_EN */
        DI_SYNC_NONE,     /* CNT_POLARITY_CLR_SEL */
        DI_SYNC_NONE,     /* CNT_POLARITY_TRIGGER_SEL */
        0,         /* COUNT UP */
       0        /* COUNT DOWN */
        );

[johnson_jl]

Dear LiQiang,

For what you mentioned:

With the 8 bits BT656 interface, for each line of NTSC, we will output (1440 + 276) bytes, and there are total 525 lines for each frame, I don't know what's your meaning of 3432.

By the way, for the blanking video, we havne't output "0x80 0x10 0x80 0x10" for all of them, some blanking video will be filled with all 0x00; that means if you are checking "0x80 0x10" for all blank video, there will be issue.

How can I change 0x00 in blanking video to 0x80 0x10 0x80 0x10?  We faved this issue that our encoder output dark green video between frames(should be blanking).

Johnson

[qiang_li-mpu_se]

Hi Johnson,

I think you should check the EAV/SAV for blanking video, not the content. It is very diffcult for IPU microcode to generate different blank data "0x80 0x10" for blank video.

[qiang_li-mpu_se]

Hi Darren, before released this BT656 output patch, we had captured all datas of the BT656 frame, and it was confirmed there are both EAV and SAV data.

You can use logical analyzer to capture all data on the 8 data line to verify it. By the way, can you attach your kernel boot up log here?

[darrenwang]

Please refer the log file.

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[qiang_li-mpu_se]

There is no error in the log, please show us the information how did you find "imx6 sent twice EAV , not send SAV + EAV".

[darrenwang]

Hi Qiang Li:

Please refer the waveform.

Thank you.

[qiang_li-mpu_se]

The patch will output data with followed EAV and SAV code:

FF 00 00 B6 ... ... FF 00 00 AB ... ...     (Repeat for 22(19) lines)
FF 00 00 9D ... ... FF 00 00 80 ... ...     (Repeat for 288(240)lines)
FF 00 00 B6 ... ... FF 00 00 AB ... ...     (Repeat for 2(3)lines)
FF 00 00 F1 ... ... FF 00 00 EC ... ...     (Repeat for 23(20)lines)
FF 00 00 DA ... ... FF 00 00 C7 ... ...     (Repeat for 288(240)lines)
FF 00 00 F1 ... ... FF 00 00 EC ... ...     Repeat for 2(3)lines

FF 00 00 B6 ... ... FF 00 00 AB ... ...     (Repeat for 22(19) lines)
FF 00 00 9D ... ... FF 00 00 80 ... ...     (Repeat for 288(240)lines)
FF 00 00 B6 ... ... FF 00 00 AB ... ...     (Repeat for 2(3)lines)
FF 00 00 F1 ... ... FF 00 00 EC ... ...     (Repeat for 23(20)lines)
FF 00 00 DA ... ... FF 00 00 C7 ... ...     (Repeat for 288(240)lines)
FF 00 00 F1 ... ... FF 00 00 EC ... ...     Repeat for 2(3)lines...

[darrenwang]

Dear Qiang:

正常horizontal (1440 + 276) * 2 =3432 畫面會正常.

但我們I.MX6 輸出到終端,使用接收端tool 量測卻為6864.

目前只剩這個數值是有差異的，想請問一下在CODE方面有哪些可注意嗎?

thank you.

[qiang_li-mpu_se]

Hi Darren,

With the 8 bits BT656 interface, for each line of NTSC, we will output (1440 + 276) bytes, and there are total 525 lines for each frame, I don't know what's your meaning of 3432.

By the way, for the blanking video, we havne't output "0x80 0x10 0x80 0x10" for all of them, some blanking video will be filled with all 0x00; that means if you are checking "0x80 0x10" for all blank video, there will be issue.

[tollerhecht]

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- i.MX6 solo output BT.656 issue (MCIMX6S5EVM10AB)" sent on 06/18/2014

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[darrenwang]

Hi Qiang Li:

標準SPEC 設定應該為圖一搭配表一，但我們實際量出來卻為圖(一)與表(二)

想請問參數需要修改哪邊嗎?

圖(一)

表(一)

圖(二)

表(二)

[qiang_li-mpu_se]

Hi Darren, I can't identify which picture is for 图一,图二,表一,表二. The reference code had only supported the standard 720*480i mode. It can be found as followed:

* hsync_len: EAV Code + Blanking Video + SAV Code (in pixel clock count)

*         For BT656 NTSC, it is 4 + 67*4 + 4 = 276.

*         For BT1120 NTSC, it is 4 + 67*2 + 4 = 142.

*         For BT656 PAL, it is 4 + 70*4 + 4 = 288.

*         For BT1120 PAL, it is 4 + 70*2 + 4 = 148.

*

* vsync_len: not used, set to 1

*/

static struct fb_videomode bt656if_modedb[] = {

{

  /* NTSC Interlaced output */

  "BT656-NTSC", 60, 720, 480, 37037,

  19, 3,

  20, 3,

  276, 1,

  FB_SYNC_HOR_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT,

  FB_VMODE_INTERLACED,

  FB_MODE_IS_DETAILED,},

The above 19, 3, 20, 3 are lines as in table of "image003.png".

So "image003.png" and "image004.png" is current NTSC mode output data.

[darrenwang]

Dear Qiang:

想請問使用BT.656 port(8 bits data + clk), 為何不能支援到480p , 是哪邊的硬體極限或是其它問題?

thank you.

[qiang_li-mpu_se]

Hi Darren, the current IPU BT656 microcode is only for interlaced display mode, we haven't implemented the prograssive mode microcode, we think for prograssive mode, it is more easy to use VSYNC/HSYNC mode.

[tollerhecht]

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[weidong_sun]

Hello Darren,

     Would you like to paste connections of CPU-->TW8836 here ? Let me check if hardware connection is correct!

Regards,

Weidong