ADV7280 teletext detected not working

Hi,

Do you have one of our evaluation board for ADV7280?

Are you using any specific scripts from ADV7280 / ADV7280-M Design Support Files ?

Have you tried the same on evaluation board and observe same behavior?

Best Regards,

Jeyasudha.M

Hello Jeyasudha.M

I have no evalboard.

I started with the CVBS fast switch script.

Because SECAM has not worked with this, I used the CVBS Autodetect script.

Now I use these settings:

static const UCHAR adv7280_RegInitTable[] = {

                               //0x0F, 0x00,                     //exit power down mode

                               0x00, 0x00,                         //CVBS in on AIN1

                               MAP, 0x80,                        //ADI REQUIRED WRITE

                               0x9C, 0x00,                        //ADI REQUIRED WRITE

                               0x9C, 0xFF,                        //ADI REQUIRED WRITE

                               MAP, USER_SUB_MAP,                              //Enter User Sub Map

                               0x03, 0x8C,                        //Enable Pixel & Sync Output drivers, VBI unfiltered

                               0x04, 0xb4,                        //Power-up INTRQ, HS & VS pads

                               0x13, 0x00,                         //Enable INTRQ output driver

                               0x17, 0x41,                         //Enable SH1

                               0x1D, 0x40,                        //Enable LLC output driver

                               0x52, 0xCD,                        //ADI REQUIRED WRITE

                               0x80, 0x51,                         //ADI REQUIRED WRITE

                               0x81, 0x51,                         //ADI REQUIRED WRITE

                               0x82, 0x68,                         //ADI REQUIRED WRITE

                               MAP, INT_VDP_SUB_MAP,                       //Select Int/VDP Map

                               //VDP_CONFIG_1, 0x8D,

                               VDP_CONFIG_1, 0x85,

                               VDP_ADF_CONFIG_1, 0xB5,      //teletext decoding enabled in bytemode DID = 0x15, SDID = 0x2A

                               0x64, 0x80, // Enable manual line programming of VBI data. Config VBI decoding on line 318 (PAL)

                               0x65, 0x00, // Config VBI decoding on line 6/319 (PAL)

                               0x66, 0x11, // Config VBI decoding on line 7/320 (PAL) for TTXT

                               0x67, 0x11, // Config VBI decoding on line 8/321 (PAL) for TTXT

                               0x68, 0x11, // Config VBI decoding on line 9/322 (PAL) for TTXT

                               0x69, 0x11, // Config VBI decoding on line 10/323 (PAL) for TTXT

                               0x6A, 0x11, // Config VBI decoding on line 11/324 (PAL) for TTXT

                               0x6B, 0x11, // Config VBI decoding on line 12/325 (PAL) for TTXT

                               0x6C, 0x11, // Config VBI decoding on line 13/326 (PAL) for TTXT

                               0x6D, 0x11, // Config VBI decoding on line 14/327 (PAL) for TTXT

                               0x6E, 0x11, // Config VBI decoding on line 15/328 (PAL) for TTXT

                               0x6F, 0x20, // Config VBI decoding on line 16/329 (PAL) for VPS/---

                               0x70, 0x00, // Config VBI decoding on line 17/330 (PAL)

                               0x71, 0x00, // Config VBI decoding on line 18/331 (PAL)

                               0x72, 0x11, // Config VBI decoding on line 19/332 (PAL) for TTXT

                               0x73, 0x11, // Config VBI decoding on line 20/333 (PAL) for TTXT

                               0x74, 0x11, // Config VBI decoding on line 21/334 (PAL) for TTXT

                               0x75, 0x11, // Config VBI decoding on line 22/335 (PAL) for TTXT

                               0x76, 0x40, // Config VBI decoding on line 23/336 (PAL) for WSS/---

                               0x77, 0x00, // Config VBI decoding on line 24/337 (PAL)

                               0x9C, 0x00,

                               MAP, USER_SUB_MAP,                              //Select User Map

                               0xFF, 0xFF                          //0xFF is not used

Exit power down mode is done later.

Changing some of the settings had no effect on teletext decoded bit.

Perhaps there are some additional  ADI required writes for VBI decoding?

Best regards

Ulrich

Von: JeyasudhaMuthuPerumal

Gesendet: Dienstag, 28. März 2017 11:29

An: Weiss Ulrich

Betreff: Re:  - Re: ADV7280 teletext detected not working

EngineerZone <https://ez.analog.com/?et=watches.email.thread>

Re: ADV7280 teletext detected not working

reply from JeyasudhaMuthuPerumal<> in Video - View the full discussion<https://ez.analog.com/message/295590?commentID=295590&et=watches.email.thread#comment-295590>

Hi,

Let me check with part specialist on these questions

Best Regards,

Jeyasudha.M

Hello,

The teletext support may not work correctly in fast switch mode. Could you please check if this works correctly when the ADV7280 is configured with a standard autodetect script.

Analog Devices recommended scripts can be found here: ADV7280 / ADV7280-M Design Support Files 

regards,

Robert Hinchy

Applications Engineer,

Analog Devices Inc.

Hello Robert,

the settings above, which I used, are based on standard autodetect script.

best regards

Ulrich 

Hi Ulrich,

I tested this in the lab.

When teletext is detected by the ADV728x, the TTXT_AVL bit will go high (Interrupt map, register 0x78 bit [7]). However this bit will remain high until cleared. This ensure that the teletext signal which only appears briefly on some lines of video is detected.

The TTXT_AVL bit will remain high until it is cleared. To clear the TTXT_AVL bit write 0x80 to Interrupt map, register 0x78. The clear bit ofr the TTXT_AVL bit is missing from the ADV728x hardware manual. I will ensure that this is inserted in the next revision of this document.

Note that a read only register and a write only register share the address Interrupt map, register 0x78.

regards,

Robert Hinchy

Applications Engineer,

Analog Devices inc.

Hello Robert,

now it's working like expected,

Thanks and best regards

Ulrich