PRIM_MODE[3:0],VID_STD[5:0],V_FREQ[2:0],
PRIM_MODE[3:0]:0101 : HDMI-COMP 暂时不知道为啥这样设置.
VID_STD[5:0]:001010 : Input Video:PR 1x1 525p,Output Resolution:720 x 480p Input Video:PR 1x1 525p,就是480p,不论PAL,还是NTSC;可以用示波器求证;
1.即将信源调整为HDMI480P,测量HS_Freq=31.4688KHz,VS_Freq=59.9406Hz;
2.LinesPerFrame=(1/VS_Freq)/(1/HS_Freq)=525;
3.示波器观察LinesOfVS_Blanking=6,得出LinesOfVS_Active=525-6=519;
4.示波器观察PixelClk=54.0005MHz,而HS_Freq=31.4688KHz,得出PixelClkCnt=(1/HS_Freq)/(1/PixelClk)=1716
5.测量HS_Blanking=2.300us, 得出PixelClkPerHS_Blanking=HS_Blanking/(1/PixelClk)=124
6.每行有效的clk是1716-124=1592;
7.而"8-bit SDR ITU-656 mode",所以每行有效的像素数是:1592/2=796
8.综上 796*519像素点PerFrame.
V_FREQ[2:0],A control to set vertical frequency of HD component standards.(用来控制设置HD分量标准信号的垂直频率,简单点就是frame_rate). 000 - 60 Hz 001 - 50 Hz 那么怎么知道是60Hz还是50Hz? 很简单,用示波器量一下HS的频率即可;
另外,1x1表示1比1采样, 1x2表示2比1采样即压缩.
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PRIM_MODE[3:0]:0101:
VID_STD[5:0]:001010:
V_FREQ[2:0]: