topic Re: Problem with VIU when using ITU656 in Vybrid Processors

Problem with VIU when using ITU656

slw — Tue, 25 Nov 2014 12:54:45 GMT

Hi,

We connected a analog camera to an external video-decoder (adv7180) which is connected to the viu using the 8bit itu656-interface (Vybrid VF512R3CMK4).

When we start the video-decoder it sends out the serial protocol, and we can see correctly the protocol (SAV/EAV starting with FF 00 00 XX, where XX has different state for field/vsync/hsync, ...)

The VIU detects field-irqs, but we don't get any vsync-irq.

Although we don't get any error-irqs, so it seams that the received protocol is correct (see ecc-errors in scr-register of viu), but the internal decoder from the viu-module doesn't generate a vsync-irq.

Has anybody use the viu using the 8bit itu656-mode ??

Here's the pining

PTC2 -> VIU_DATA2

PTC3 -> VIU_DATA3

PTC4 -> VIU_DATA4

PTC5 -> VIU_DATA5

PTC6 -> VIU_DATA6

PTC7 -> VIU_DATA7

PTC8 -> VIU_DATA8

PTC9 -> VIU_DATA9

PTB16 -> VIU_DATA10

PTA7 -> VIU_PIX_CLK

Another question is : How does the viu differ between 8bit and 10bit itu656-mode ?

Regards

Sebastian

Re: Problem with VIU when using ITU656

naoumgitnik — Tue, 25 Nov 2014 17:17:07 GMT

Dear Sebastian,

Before we dig deeper... why are you not using Vybrid's Video ADC (VADC) inputs intended for analog video signals?

Sincerely, Naoum Gitnik.

Re: Problem with VIU when using ITU656

slw — Tue, 25 Nov 2014 17:44:46 GMT

Hi Naoum,

See Re: Vf6xx - Contact image sensor - VideoADC

IMHO it is not possible to write a good driver for AFE and VDEC with that kind of documentation.

In your sample-code that you attached to the above discussion, you use registers that are even not in the memory map.

So we decided to use an external video decoder and only use the viu.

As explained above the external video decoder works fine but the viu-mdule .....

I hope there is a software-solution for that problem.

Regards Sebastian

Re: Problem with VIU when using ITU656

naoumgitnik — Tue, 25 Nov 2014 22:34:14 GMT

Dear Sebastian,

Is my understanding correct that the major obstacle on the way to using the analog video inputs is lack of information about some registers? - It is a real pity that you have not stressed this point prior to redirecting your effort towards using an external video-decoder.

I agree with you that our documentation is not perfect, but the point here is that our software engineers somehow learned about these registers while developing Vybrid analog video-input drivers, and I can contact them to see if I can get this information.

This information might be "for factory use only", but most likely we can resolve these issues, e.g., by signing an NDA.

Your opinion, please?

Sincerely, Naoum Gitnik.

Re: Problem with VIU when using ITU656

slw — Wed, 26 Nov 2014 09:04:46 GMT

Dear Naoum,

It's not only the lack of information about these additional registers. There is not enough information about several registers and the internal function. To write a driver for the video subsystem is at the moment more like try-and-error than really developing it. It would be nice to get more information about it when available. But this is not that important.

At the moment it is much more important for us to fix the with viu problem when using ITU656.

Regards

Sebastian

Re: Problem with VIU when using ITU656

kef2 — Wed, 26 Nov 2014 14:23:31 GMT

Sebastian,

VIU interrupt flags are w1c flags. Isn't it that you clear VSYNC_IRQ while trying to clear only FIELD_IRQ?

VIU3_SCR |= VIU3_SCR_FIELD_IRQ_MASK; // in fact clears ALL VIU3 interrupt flags.

proper way to clear only FIELD_IRQ flag would be this

VIU3_SCR = (VIU3_SCR & ~0x003F0000) | VIU3_SCR_FIELD_IRQ_MASK;

Edward

Re: Problem with VIU when using ITU656

slw — Wed, 26 Nov 2014 14:56:08 GMT

Dear Edward,

You are right. And our driver is doing it exactly this way ;-)

Problem is, that we didn't get an vsync-interrupt, even when we stop cpu using a jtag-debugger.

When cpu is in break-state we see in the viu registers that field-state toggles but there is never an vsync-irq.

Sebastian

Re: Problem with VIU when using ITU656

naoumgitnik — Wed, 26 Nov 2014 16:35:18 GMT

Dear Timesys Support ,

May you help the customer from the "software point view”, please?

Thanks in advance, Naoum Gitnik.

Re: Problem with VIU when using ITU656

karina_valencia — Thu, 27 Nov 2014 22:42:18 GMT

timesyssupport can you help to attend this case?

Re: Problem with VIU when using ITU656

timesyssupport — Mon, 01 Dec 2014 18:18:38 GMT

Hello karinavalencia and naoumgitnik,

As noted in this other thread https://community.freescale.com/thread/321908 - we do not currently have a VIU driver in the Linux kernel. There may be efforts made in the kernel update we are working on to add one, but at this time, we can offer no in depth assistance in this matter.

Regards,

Timesys Support

Re: Problem with VIU when using ITU656

VilemZ — Thu, 11 Dec 2014 13:52:43 GMT

Hi,

I think, that you connect a few pins. If you use VIU, you need connect by VSYNC and HSYNC. Then you can use IRQ from these.

And have you got true setting of VIU? Can you send your register setting?

Regards,

Vilem

Re: Re: Problem with VIU when using ITU656

slw — Mon, 15 Dec 2014 13:34:16 GMT

Hi,

In RM (version 7) there is a table in chapter 57.3 "Video Input Signal Mapping", where HSYNC, VSYNC, DE and FID is not connected for ITU656.

In chapter 57.5.3 "Decoder" is explained that HSYNC, VSYNC and FID are extracted from the ITU656-protocol. That's why we didn't connect these signals.

Do we have to connect them ?

I have attached an register-dump in a situation where we initialized the external decoder (which sends the 656-protocol).

The field-number changes periodically, so it seems that the decoder can successfully extract it, but we don't get any VSYNC-irq.

Regards,

Sebastian

Re: Problem with VIU when using ITU656

VilemZ — Tue, 16 Dec 2014 13:53:10 GMT

Hi,

It's true. I'm sorry. It is my fault. For connections:

I think that you don't need VIU_DATA10 (chapter 57.3 in RM). You need only from VIU_DATA2 to VIU_DATA9. But this connection isn't correct. VIU_DATA10 must to be connect to pin PTB19 (ALT6 for mux).

And VIU_DATA9 is not correct connection. In chapter 5.1 in RM is table for PIN MUX and for VIU_DATA9 you need connect to PTB18 (ALT6 for MUX).

Another question is : How does the viu differ between 8bit and 10bit itu656-mode ?

To avoid confusion between 8-bit and 10-bit representations, the eight most significant bits are considered to be an

integer part while the two additional bits, if present, are considered to be fractional parts

For example, the bit pattern 10010001 would be expressed as 145d or 91h, whereas the pattern 1001000101 is expressed

as 145.25d or 91.4h.

From this documet: http://www-inst.eecs.berkeley.edu/~cs150/Documents/ITU656.PDF (page 2 - NOTE 1)

Can you try now?

And why do you use external video-decoder. You can use analog input in Vybrid.

Is ok?

Vilem

Re: Problem with VIU when using ITU656

slw — Tue, 16 Dec 2014 14:42:52 GMT

Hi Vilem,

I have reviewed our hardware. My connection-table above is wrong. Our hardware is connected as you described:

PTC2 -> VIU_DATA2

PTC3 -> VIU_DATA3

PTC4 -> VIU_DATA4

PTC5 -> VIU_DATA5

PTC6 -> VIU_DATA6

PTC7 -> VIU_DATA7

PTC8 -> VIU_DATA8

PTB18 -> VIU_DATA9

PTA7 -> VIU_PIX_CLK

So this is not the reason why viu doesn't work.

Does anybody use successfully the viu in itu656-mode ?

Regards

Sebastian

Re: Problem with VIU when using ITU656

slw — Thu, 08 Jan 2015 16:26:07 GMT

Hi Vilem,

Any updates ?

Regards

Sebastian

Re: Problem with VIU when using ITU656

jiri-b36968 — Thu, 08 Jan 2015 17:25:46 GMT

Hi Sebastian,

I'm afraid that HSYNC_IRQ and VSYNC_IRQ interrupts as raised only when VSYNC and HSYNC signals are used (need to be confirmed with designers). ITU is using just fields (FIELD_IRQ) and VSYNC and VSYNC are decoded.

Please try to use DMA_END_IRQ (VSTART_IRQ). Do you see them raising?

/Jiri

Re: Problem with VIU when using ITU656

slw — Fri, 09 Jan 2015 12:23:55 GMT

Hi Jiri,

as explained above, I only get the FIELD_IRQ. When I start the DMA-Transfer I never get an DMA_END_IRQ and DMA_ACT stays busy.

Is it even possible to use the ITU-mode without external HSYNC/VSYNC-signals connected ?

Regards

Sebastian

Re: Problem with VIU when using ITU656

jiri-b36968 — Fri, 09 Jan 2015 14:18:02 GMT

Hi Sebastian,

HSYNC/VSYNC are decoded from field in the case of ITU. No external HSYNC/VSYNC signal. Each received field triggers FIELD_INT. I would expect that is should generate also others interrupts after decoding. Since you say that it is not generated I'm going to ask designers and validation team. Stand-by.

/Jiri

Re: Problem with VIU when using ITU656

jiri-b36968 — Thu, 15 Jan 2015 12:53:46 GMT

Hi Sebastian,

designers claim that V/H sync should be generated in ITU mode.

Could you check if interval between FIELD_IRQ equals to one field and it is regular? Do you see correct field received - with V and H sync information?

/Jiri

Re: Problem with VIU when using ITU656

slw — Tue, 27 Jan 2015 12:32:35 GMT

Hi Jiri,

Sorry for my late answer but I was ill the last 2 weeks.

I have attached some example records where you can see the relevant ITU data-stream (SAV/EAV starting 0xFF, 0x00, 0x00).

Regards

Sebastian