vpif configuration

Hi,

Thanks for your post.

In my opinion, in the code, it actually VPIF driver API function "VPIFCaptureClkedgeModeSelect" to select the edge of the pixel clock that data is captured on. So, if you check the API code snippet below, the bit compliment of VPIF_C0CTRL_CLKEDGE which is ~VPIF_C0CTRL_CLKEDGE which is used in the code for C0 CTRL registers and thereby, if you take compliment the 31 bit which is CLKEDGE as per section 34.3.2 Channel 0 Control Register (C0CTRL) in the C6748 TRM, the bit would be become reverse.  Please check the code snippet in the below path:

~\Texas Instruments\pdk_C6748_2_0_0_0\C6748_StarterWare_1_20_03_03\drivers\vpif.c

void VPIFCaptureClkedgeModeSelect(unsigned int baseAddr, unsigned int channel, unsigned int mode)
{
    unsigned int temp;
    if(channel==VPIF_CHANNEL_0)
    {
        temp = HWREG(baseAddr + C0CTRL) & ~VPIF_C0CTRL_CLKEDGE;
        HWREG(baseAddr + C0CTRL) = temp | mode;
    }
    else if(channel==VPIF_CHANNEL_1)
    {
        temp = HWREG(baseAddr + C1CTRL) & ~VPIF_C1CTRL_CLKEDGE;
        HWREG(baseAddr + C1CTRL) = temp | mode;
    }
}

and as per the above code, the macro "VPIF_C1CTRL_CLKEDGE" is defined in the include file "hw_vpif.h"  and the file you can see in the below C6748 starterware installation path

~\Texas Instruments\pdk_C6748_2_0_0_0\C6748_StarterWare_1_20_03_03\include\hw\hw_vpif.h 

and actually, the value of VPIF_C0CTRL_CLKEDGE is 0x80000000 and its compliment would be 0x7FFFFFFF which is used in the API "VPIFCaptureClkedgeModeSelect" to select the edge mode of the pixel clock. Kindly review the above code & validate the same.

/* C0CTRL */

#define VPIF_C0CTRL_CLKEDGE (0x80000000u)
#define VPIF_C0CTRL_CLKEDGE_SHIFT (0x0000001Fu)

Thanks & regards,

Sivaraj K

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Please click the Verify Answer button on this post if it answers your question

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Hi Sivaraj,

I already knew the VPIFCaptureClkedgeModeSelect function, where the important will be mode. Mode will select falling or rising. But I couldn’t find the function call from the entire SDK so couldn’t decide what “mode=1” means.

void VPIFCaptureClkedgeModeSelect(unsigned int baseAddr, unsigned int channel, unsigned int mode)
{
    unsigned int temp;
    if(channel==VPIF_CHANNEL_0)
    {
        temp = HWREG(baseAddr + C0CTRL) & ~VPIF_C0CTRL_CLKEDGE;
        HWREG(baseAddr + C0CTRL) = temp | mode;
    }

...

}

I'll do some more  tests with EVM.

Regards, Devin