NHD-5.0-800480TF-ATXL#-T with the FT800 EVE GFX Engine



  • Paul_B


    I’m sorry, unfortunately I am not familiar with the FT800 gfx engine. However, I am more then happy to help out with your timing issues!

    To figure out the required timing parameters open up the NHD-5.0-800480TF-ATXL#-T datasheet (Page 6) or HX8264-D02 datasheet (Page 55)

    Link: http://www.newhavendisplay.com/specs/NHD-5.0-800480TF-ATXL-T.pdf
    Link: http://www.orientdisplay.com/pdf/HX8264-D02.pdf

    The code snip-it below is an example of how your timing parameters should be set up on the NHD-5.0-800480TF-ATXL#-T display.

    Linux Example:

    display-timings {
    + native-mode = <&timing0>;
    + /* Settings for NHD-5.0-800480TF-ATXL#-T: */
    + timing0: 800x480 {
    + clock-frequency = <30000000>;
    + hactive         = <800>;
    + vactive         = <480>;
    + hback-porch     = <40>;
    + hfront-porch    = <40>;
    + hsync-len       = <48>;
    + vback-porch     = <29>;
    + vfront-porch    = <13>;
    + vsync-len       = <3>;
    + hsync-active = <0>;
    + vsync-active = <0>;
    + };

    Hope this helps!

  • rtilson

    I will try those values but I will be running up against the the FT800 limitations. Am I able to drive the TFT display at a resolution of 480x272?

  • Paul_B


    Yes you can, however the values attached are verified to work.

    Good luck!

  • rtilson

    Awesome thanks Paul_B. Knowning this allows me to further eliminate potential failure variables.

    Would you be able to tell me what the relationship is between the PCLK and the hactive, hfront-porch, hback-port values? For the values you given for Linux, if I were to adjust the PCLK to say from 30MHz to 35MHz, 48MHz, how would the H/VSync, H/V*-Porch values change?

    In my current setup I have a choice of PCLK speeds that can be set to 48MHz, 24Mhz, 16MHz,etc (div 1,2,3,etc).

  • Paul_B


    PCLK is used to control panel refresh rate.
    VSYNC is used to reset the LCD row pointer to top of the display.
    HSYNC is used to reset the LCD column pointer to the edge of the display.

    Regarding the PCLK, adjusting these values should not affect the H/VSync, H/V*-Porch values.

    If you would like to learn more about LCD signal interface and timing parameters I highly recommend reading through this power-point:

    Link:  http://www.nxp.com/wcm_documents/techzones/microcontrollers-techzone/Presentations/graphics.lcd.technologies.pdf

  • rtilson

    Awesome! I will have that committed to memory soon enough.

  • rtilson

    As a matter of completeness on the topic subject. I came across application node "AN_240 FT800 From the Ground Up.pdf" on the FTDI EVE website that explains which signals are controlled by which registers.

  • rtilson

    I have encountered some interesting effects* when it comes to setting the "One Horizontal Line" to less than 810. The datasheet specifies the minimum for this part to be 889. However, it appears that 810 for the HX8264-D02 wouldn't be out of it's timing capability.

    Are the minimum horizontal cycle timings dependent on how the HX8264-D02 implemented on the product?

    Following the HX8264-D02.pdf page(pdf) 59 specifications

    Horizontal Disp Area (HDA) = 400
    One Horizontal line (OHL) = 520
    Horizontal Pulse Width (HPW) = 1
    Horizontal Back Porch (HBP) = 88
    Horizontal Front Porch (HFP) = 32

    Vertical Disp Area (VDA) = 240
    Vertical Period Time (VPT) = 270
    Vertical Pulse Width (VPW) = 1
    Vertical Back Porch (VBP) = 17
    Vertical Front Porch (VFP) = 13

    For "One Horizontal Line" the formula is:
    OHL = HDA + HPW + HBP + HFP : With current values it adds to 521, which is within spec giving on this page.

    For "Vertical Period Time" the formula is:
    VPT = VDA + VPW + VBP + VFP : As with the "One Horizontal Line" it adds to 271, which again is within spec.

    *Interesting Effects:
     I get alternating black/white bars on the screen for any OHL values of less than 810. 

    I am beginning to think that this part isn't a good match for what I'm trying to use, because the native resolution of this part is 800x480 and the FT800 has a max resolution of 512x512 but supports 5 inch displays ().

    On the upside I do have a better understanding on how I might drive this display, but I'm _very_ limited on what I can drive it with.

  • rtilson

    I have eliminated the part as a potential issue and isolated it down to the gfx engine and initialization of the engine itself.


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