Display Module

From ESS-WIKI
Revision as of 03:37, 8 February 2017 by Chang.qing (talk | contribs)
Jump to: navigation, search
→Hardware Module

display timing setting on SDK

If you want to select or change the type of LVDS panel, please set the parameter of "native-mode" in linux-4.1.6+gitAUTOINC+52c4aa7cdb-g52c4aa7/arch/arm/boot/dts/am335x-rsb4221.dts file to your panel parameter, which is shown as below:

display-timings {
native-mode = <&timing2>;
...
...
timing2: 1360x768 {
hactive = <1024>;
vactive = <768>;
hback-porch = <120>;
hfront-porch = <120>;
hsync-len = <104>;
vback-porch = <20>;
vfront-porch = <20>;
vsync-len = <1>;
clock-frequency = <60000000>;
hsync-active = <0>;
vsync-active = <0>;
};
};

The definition of da8xx_panel in linux-3.2.0/ drivers/video/da8xx-fb.c: The name field is optional. If you input this value, it can be used in U-Boot environment settings. The refresh field is the screen refresh frame rate, such as 60Hz, 70Hz. The resolution can be filled in the xres & yres fields. The pixel clock (pixclock) is equaled to 10ʌ12 /(Total horizontal line * Total vertical line * DCLK). For example, the total horizontal line is 1344 DCLK, and total vertical number is 806 horizontal lines. The frame rate is 60 MHz. Therefore, we can get 10 12 /(1344*806*60) = 15385.
The margin values can be seen as front porch & back porch.
The sync_len means pulse width.
The sync value indicates the sync polarity (low or high).