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Original question:

SK-AM62: bare-metal mipi dpi code

SK-AM62: minimum stack to draw pixel on display

Seyed M Safaei
Intellectual 540 points

Part Number: SK-AM62

Hi Experts,

I'm asking this question as a follow-up on my previous question here: e2e.ti.com/.../sk-am62-bare-metal-mipi-dpi-code

What I want to know, is how I can draw white pixels (let's say a rectangle border or a character) using TI DSS. I know that the display framework in Linux is super complicated but I just want to draw pixels at certain points of the display. how do I go about it?

So my ideal case is a bare minimum amount of code, let's say I just write some pixel format to a framebuffer and say hey I want these pixels at this location,s and then see the results  (white pixels turned on) on my HDMI monitor. how simple is doing something like this? does the DSS module work in a way that you only want to directly reflect what's in a framebuffer on a display? again I don't want any graphics or colors or anything fancy. just want to turn pixels on!

my ultimate goal is bare metal but if you can help achieve this with Linux, that works too. (like what's the bare minimum stack for Linux?)

Thanks a lot.

  • 0
    TI__Mastermind 45035 points

    Hello,

    We don't have any such examples and my recommendation would be to search web for simple DRM/KMS examples.

    Regards,
    Krunal

  • 0 in reply to Krunal Bhargav34
    Intellectual 540 points

    Thanks. I noticed there is a dss and fvid2 driver for am65 on RTOS sdk (which has the same architecture and video output as am62)

    1. Would that work for MIPI DPI? There are OLDI examples for am65x , so I was wondering how much overlap this can have for running something on DPI output. I assume many of the steps to put an image on screen should remain the same. 

    2. It appears that fvid2 is driver independent, is that right? If it is, then someone can use that with a dpi dss driver (right now the dss is towards oldi lvds i guess but I can write the dpi driver if I can reuse some of the stuff from fvid2 and/or dss)

    I appreciate if you offer some guidance on these two questions. So that I can learn how the DSS and FVID2 work.

    ill make sure to post any progress on mipi dpi driver development for am62 here so that other people can use in the future. I appreciate if you notify your display experts to help me here! Thanks.

  • 0 in reply to Seyed M Safaei
    TI__Mastermind 45035 points

    Hello,

    There are two aspects here that I would like to highlight:

    1. If you are not planing on using Linux, we offer MCU+ SDK but it's only running on the M4F and R5F cores: Here is the link: https://software-dl.ti.com/mcu-plus-sdk/esd/AM62X/08_04_00_16/exports/docs/api_guide_am62x/RELEASE_NOTES_08_04_00_PAGE.html. Currently, we are not supporting DSS driver with the MCU+ SDK. As you recommended in previous post, using the AM65x driver as a starting point is a valid because it's a similar HW on both platforms. However, I cannot comment on the feasibility aspects because our SW dev team has not tested or verified the DSS path.

    2. If you are using Linux, my recommendations would be to review the following user space examples:
    https://github.com/dvdhrm/docs/tree/master/drm-howto
    https://github.com/tomba/kmsxx/tree/master/kms%2B%2B/src

    The above examples are based on C++ and they use standard DRM APIs to control your display. In option 2, you don't have to write the baremetal driver for DSS and Linux driver is already present. However, you would need to get familiar with the DRM framework.  

    Regards,
    Krunal