How do I configure DM6446 to support LCD output?

Another good resource on this is the Digital Video Using Davinci application note, co-authored by Juan himself :). Though the actual drivers used are out of date (the current DVSDK includes such drivers), the discussion on the color formats and workings of the drivers could come in quite handy in implementing your own LCD solution.

I would recommend the App Note for some background info on video basics, hardware and general software architecture;  however, the newer DVSDK Linux kernels have digital video output capability built-in already (was not the case when we wrote the App Note).  Therefore, in order to simplify support for digital video output, I would refrain from using the software included in the App Note (it is based on old DVSDK and out-dated).  Just a small note to make sure our customers do not waste time.

By the way, I will be in need of configuring digital output to LCD with dm6437 after one or two weeks. Is there any example or document you would recommend?

Unfortunately a LCD display on the DM6437 is one of the applications we have little on, the closest would be the DM644x document above since the DM6437 shares the same VPBE, so the register level settings should be about the same even though the software architecture is entirely different.

There may be some third party support for this out there though, there is a daughterboard for the DM6437 EVM available from D3 Engineering that has a LCD interface on it, they may have driver software for the DM6437 that can handle a LCD display.

Hi Bernie and Juan,

Today I started working on interfacing DM6437 to LCD. I am looking for every help I can use, because if this job is only up to VENC register definitions, it seems a little desperate.

I think you mean the Digital Video Using the DaVinci SOC document by "DM644X document above", am I right? If the register level settings are same or plenty same, of course it will incredibly come in handy. But what do you mean by the "software architecture is entirely different"?

Also I mailed a few places like D3 Engineering and waiting for response.

Thank you in advance,

Erman

Erman,

Yes, Digital Video Using the DaVinci SoC is the correct document; it should be a good guide to show you which registers you need to program on DM6437 to achieve this.

I believe what Bernie meant by the software architecture being different is that on DM6446 EVM, the drivers that would have these register definitions are based on Linux and follow pre-defined Linux standards (V4L2 and/or FBDev), whereas on DM6437 you have DSP/BIOS based drivers (no ARM or Linux) and follows our IOM standard.  As you can imagine, the software architectures are somewhat different.

However, you can take the existing DM6437 display driver (C code) and add functions similar to the ones described in the App Note to allow you to switch to/from LCD mode.

Juan,

Thank you. These are good news to me. If the VPBE registers are the same with DM6437 and DM6447, and if it is defined which registers I should fill, then the software part that defines how I should write to these registers is not a problem.

Also one thing I do not understand is the daughter board concept. What do they do? Everywhere I look, interface to LCD is done using a daughter board. If we do have the right connecter on the board, we could interface to LCD using DM6437 without daughter board, right?

Thank you again...

Eric,

The DLCD controller in the VPBE is itself a ready-to-use LCD interface with the basic signals which can be brought out to the LCD. You can simply tape out the signals out to a appropriate connector on the board. However, I think some LCDs, like the THS8200 need some I2C support as well along with some seperate chips, which would neccessitate a daughter board!. I think the LogicPD LCD can be connected directly to the DM6446 (I havent that; so cannot confirm if it is a daughter card or not).

Erman,

As Sundar suggested, the internal digital LCD controller inside DM6437 can be used to connect directly to LCD; however, as you can see, there is no digital LCD connector (RGB, DVI, HDMI...) readily available on our EVM, hence the reason why you would need to build a duaghter card.

It's okay then. We have our own board which a proper connector for LCD.

Thanks all.

Dear Elric,

Were you able to connect  DM6437 with LCD? If so,  could you send an example program to  my email ars-mob at mail dot ru  or  post here. I think for many it would be useful.

Thanks,

Igor

Hi there,

It has been a long time since my last post.

Igor, unfortunately I can't send the codes, I am restricted to send codes. I was able to take digital output with DM6437. For DSP, you can take reference the document that is mentioned above. It consists a code example and good explanations. Registers for DM6437 are generally same with the one in the document. It won't be a much problem.

For LCD, you should provide the requirements in the datasheet of your LCD. Bernie and Juan were quite helpfull, if they are still around they will surely help. As in the Juan's post, there is no digital connector in EVM, so you will need a daughter board.

Erman

Dear Erman,

I understand, you are right. Thanks a lot for your answer

Igor