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Nations Technologies Inc.
Tel
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+86-755-86309900
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Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
28.2.2
Interface Timing
Figure 28-1 DVP interface timing example
DVP_PCLK
DVP_VSYNC
DVP_HSYNC
DVP_D[7:0]
As shown in above figure:
DVP_PCLK is the pixel clock, and capture 1 byte (8bit) of valid data per clock cycle;
DVP_VSYNC is a vertical sync (frame sync) signal, active high;
DVP_HSYNC is the horizontal sync signal, active high;
When DVP_VSYNC and DVP_HSYNC are both high level, the data is valid;
There is a gap of at least one pixel clock cycle between every two lines;
According to the timing in the above figure, the user needs to configure DVP_VSYNC and DVP_HSYNC in
the DVP module to be active high and capture data on the falling edge of DVP_PCLK to receive data correctly;
DVP data is only valid when the capture enable bit (register DVP_CTRL.CAPTURE) is 1, and the capture
enable bit must be 1 at least 4 pixel clock cycles earlier than the DVP_VSYNC valid signal (high level),
otherwise the current frame will be discarded .
Note: The DVP_VSYNC and DVP_HSYNC signals in the above figure are active high, and may also be active low in
practical applications. It is necessary to configure the signal polarity in the DVP module according to the actual
situation.
Operating Instructions
28.3.1
General operation process
1.
Turn on the clock of the CMOS optical sensor, enable the relevant control port (usually the I2C interface), and
configure the sensor parameters;
2.
DVP port and parameter configuration (for example: capture mode, window mode, DMA, etc.);
3.
Configure the capture enable bit (register DVP_CTRL.CAPTURE), ready to receive data;
4.
Turn on the CMOS sensor and start sending data.