Rockchip RK32 Series, Hardware Design Manual

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RK3288 Hardware Design Guide
Tips:

MIPI 1Lane and 2Lane will directly affect the preview frame rate and the speed of
camera;

If MIPI Camera Sensor need to be used ,it is recommended to refer to RK Verification
list:
RK_Camera_Verification_List.xlsx , to make sure debugs have been passed at
first;
13.2 PCB Layout
Recommendation for DVP PCB Layout:

MIPI Sensor connector should be placed close to chip, to shorten trace length;

MIPI Sensor signal traces should fully comply to differential specification, length
difference between two signal traces in the same pairs should be limited within 10mil,
length difference between two signal traces in different pairs should be within 30mil;
Take trace corner always as an arc or obtuse angle, not a right angle or acute angle,
impedance is Z=100ohm±10ohm;

To reduce EMI, high-speed differential signal of MIPI Sensor, should be placed on inner
layer, and make sure trace reference plane is continuous and complete, it can't be
segmented, or else it will cause discontinuousness of differential trace impedance and
increase effect on differential signal from external noise. If the trace is on PCB surface
layer, it should be surrounded by GND;

Use less vias between different layers in high-speed signal trace of MIPI Sensor if
possible, otherwise it will cause discontinuous impedance;

Clock traces like MIPI_MCLK, CIF_CLKI, CIF_CLKO are suggested to be surrounded
separately by GND, and kept away from other high-speed signal traces;

DVP Sensor signal is suggested to be routed on CIF_D0-D7, and surrounded by GND
in group.