Just recently on the Cyclone IV to a 7-inch screen light up, to catch the heat, Taobao bought this OV2640 camera module via LVDS, because the initialization is much more complicated than using Vrilog C, not as good as easy to debug C, so use STM32 initialization, module F3 and F4 reference routines, but his hand only a minimum system board F03, refer to the two reference routines transplanted SCCB code base, the first step to do the test, read the module ID has been found to read 0xFF , a lot of times to check the code, logic analyzer waveform grip, no protocol problem, the ninth SCCB also been responsive, but data is wrong. Behind only go back SCCB carefully read technical manuals provided by the official, I found the following sentence:
Follow such a sentence, suddenly aware of their own to check initialization process when the IO, and sure enough, my IO pin is set to initialize the SIO_D push-pull output, open-drain output change, compile download validation, and she correctly read ID , the other is worth noting that, after the discovery ninth SCCB send ID does not answer, you should pay attention to check whether PWDN have been pulled down in the first debugging, because the signal is active high position, that is to say if PWDN high level, the module has been in the power down state, naturally not care about you. Place a complete read reference waveform
