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questions in LIDD user guide : anybody could confirm the LIDD mode supports DMA or not

Power Pan
Expert 1985 points
Other Parts Discussed in Thread: AM1808, TMS320C6748, OMAP-L138

1. how about the DMA transfer destination in LIDD mode. describe in datasheet page 11, When the LIDD Controller is used, the DMA engine accesses the LIDD Controller's address and/or data. so, how to make sure what destination of the DMA ?

2. if I'm using LIDD interfacing 8 bit TFT but the TFT is 16bpp mode, how I could handle the data re-ordering? could LIDD do this ?

3. if the DMA needs the  palette data in LIDD mode?

registers.

Power Pan

  • 0
    TI__Genius 14405 points

    Hello,

    Power Pan said:

    1. how about the DMA transfer destination in LIDD mode. describe in datasheet page 11, When the LIDD Controller is used, the DMA engine accesses the LIDD Controller's address and/or data. so, how to make sure what destination of the DMA ?

     

    I am not sure what you are asking. But I believe you can set the the destination address of EDMA to LIDD_CS0/1_DATA register with increments set to 0.

    Power Pan said:

    2. if I'm using LIDD interfacing 8 bit TFT but the TFT is 16bpp mode, how I could handle the data re-ordering? could LIDD do this ?

    Do you have a specific display that our expert can look at?

    Power Pan said:

    3. if the DMA needs the  palette data in LIDD mode?

     See 2.4 LIDD Controller of the user guide. Palette is not supported in LIDD mode.

  • 0 in reply to Paul.Yin
    Guru 10570 points

    Hello, Paul.

    Can I confirm about your answer?

    Paul.Yin said:

    1. how about the DMA transfer destination in LIDD mode. describe in datasheet page 11, When the LIDD Controller is used, the DMA engine accesses the LIDD Controller's address and/or data. so, how to make sure what destination of the DMA ?

    I am not sure what you are asking. But I believe you can set the the destination address of EDMA to LIDD_CS0/1_DATA register with increments set to 0.

    [/quote]

    There are LIDD_CS0/1_DATA registers and LIDD_CS0/1_ADDR registers on LIDD controller.
    When we access LIDD with CPU, we should write data to LIDD_CS0/1_DATA after writing address to LIDD_CS0/1_ADDR.
    When we access LIDD with DMA, how can I write address/data to each registers?

    Your answer seems that when use DMA, address and data are written to LIDD_CS0/1_DATA and LIDD_CS0/1_ADDR regs by DMA.
    Is my understanding correct?

    Character LCD needs to be written some LCD settings(mode set, clear screen, Cursor position set etc..) before wite data to LCD.
    Since their settings are not only one, I wonder that how does dma write address/data to each registers.

    If you want to refer example source code about LIDD.
    You can get it on Logic PD site.

    http://www.logicpd.com/products/system-on-modules/omap-l138-som-m1/#documentation
    OMAP-L138 / TMS320C6748 / AM1808 SOM-M1 Gel, CCS Setup, & BSL Files (CCS v4.2.4)

    Best regards,
    RY