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dm365 using digital output instead of internal encoder

Craig Smith
Intellectual 810 points
Other Parts Discussed in Thread: THS8200, TFP410

Do the current drivers for dm365 support using the digital video output (aka LCD?) intstead of going through the internal encoder and out the component interface?

We are trying to send the video to an HDMI transmitter. I see things in the driver code that look like it may be hard-coded to use the internal encoder when selecting HD resolutions.

For example (from davinci_platform.c):

void davinci_enc_priv_setmode(struct vid_enc_device_mgr *mgr)
{

...

   } else if (strcmp(mgr->current_mode.name, VID_ENC_STD_720P_60) == 0) {
        /* DM365 has built-in HD DAC; otherwise, they depend on
         * THS8200 */
        if (cpu_is_davinci_dm365()) {
            davinci_enc_set_internal_hd(&mgr->current_mode);
            /* changed for 720P demo */
            davinci_enc_set_basep(0, 0xf0, 10);
        } else
            davinci_enc_set_720p(&mgr->current_mode);

Can someone please clarify if the drivers need to be modified to bypass the internal encoder (or any other info/details/suggestions)? Thanks.

Regards,

-Craig

  • 0
    TI__Mastermind 37340 points

    The best place to look for information on driver capabilities and limitations is the Driver Data Manual included in the DVSDK (see PSP directory).  According to this document, the DM365 driver does support digiatl RGB video output; the digital video interface is accessible via J23 connector on EVM, hence you will likely need to build a daughter card to sit on top of this connector to do anything meaningful with digital RGB video output.

  • 0
    TI__Mastermind 41665 points

    CraigSmith said:
    I see things in the driver code that look like it may be hard-coded to use the internal encoder when selecting HD resolutions.

    The specific configurations you are using like the VID_ENC_STD_720P_60 are expecting to use the on board video DACs like the code suggests, to get a digital output you can try some of the other modes described in the documentation as Juan suggests, however to get a digital output in the format you want you will likely have to modify the driver, as the PSP driver out of the box is only tested on the analog output. I understand that the code that is in there for digital output modes on other parts may work with the DM365 but is untested/unsupported, which could lead to the need for additional modifications.

  • 0 in reply to Bernie Thompson TI
    Intellectual 810 points

    OK, thanks. That's pretty much what I needed to know (confirmation that I need to change the driver). I've already started and it seems to be working. Thanks again.

  • 0 in reply to Craig Smith
    TI__Mastermind 41665 points

    I am sorry about the confusion there, our driver packages in general only cater to the EVM itself, as that is all we have to test it on, and since there are no digital output daughtercards for the DM365 EVM there is no digital output driver software yet.,

    I am very glad to hear that you have a digital output going, I was suspecting you could get at least something on the output by just enabling the digital bus and perhaps modifying a couple other bits in the VPBE, however I have not had a chance to try it yet.

  • 0 in reply to Craig Smith
    Prodigy 10 points

    Craig,

    Did you by any chance ever try DM365 parallel digital LCD output with non-standard timing?

    Thanks,

    Mohammad

  • 0 in reply to Craig Smith
    Prodigy 10 points

    Hello Craig. What kind of modifications are necessary to setup the HDMI interface for the DM365? I want to use the TFP410 from TI.