ESP32-S3接OV5640出现“Failed to get the frame on time”以及“NO-SOI”、“NO-EOI”问题的定位过程与最终解决（5）

本文链接：https://blog.youkuaiyun.com/phmatthaus/article/details/143761829

接前一篇文章：ESP32-S3接OV5640出现“Failed to get the frame on time”以及“NO-SOI”、“NO-EOI”问题的定位过程与最终解决（4）

上一回继续定位问题，讲到了是用示波器观测到VSYNC信号在新板子上不正常，由此引出两方面进一步排查的路径：

1）硬件层面，根据《OV5640_Camera_Module_Hardware_Application_Notes》仔细看一下硬件层面有没有没有注意到的；

2）软件层面，对比一下初始化以及拍照过程中的日志，看一下新旧两个版本硬件的摄像头配置是否存在差异。

先说软件层面，笔者经过新老两个版本软件打印信息的对比，发现OV5640的配置并无差异，只是新版本由于使用了PWDN和RESET引脚，多个GPIO配置的相关打印信息，这应该与本问题无关。

再说硬件层面，硬件工程师仔细翻看了手册，只找到了一处疑似怀疑的地方（保密原因，再次不详述具体点）。但是理论上应该影响不大。就在笔者准备和硬件工程师再细化差异点（现在存在SCCB和PWDN等引脚的几处差异，在飞线或者割线，把SCCB两个信号和PWDN、RESET引脚解耦）时，硬件同事突然想到了之前的一个疑似点。在《OV5640 datasheet》中的第103页，如下：

可以看到，这是与SC PWC寄存器（地址为0x3031）相关的。SC PWC中的bit3代表Bypass regulator。老板子中设置为了1，此处设置为0试一下。

为什么要这样设置呢？

因为老板子是用2.8V供电的，而新板子则使用1.8V供电。手册中写的清楚（参见笔者文章）：

简单来说就是，在2.8V供电时，内部DVDD调节器易引发热问题，因此需要旁路（bypass）这个调节器而使用外部电源；在1.8V供电时，就不用旁路了，而使用内部DVDD。

乐鑫的官方代码中，SC PWC即0x3031这个寄存器的相关代码在components/esp32-camera/sensors/private_include/ov5640_settings.h中的sensor_default_regs数组中，代码如下：

static const DRAM_ATTR uint16_t sensor_default_regs[][2] = {
    {SYSTEM_CTROL0, 0x82},  // software reset
    {REG_DLY, 10}, // delay 10ms
    {SYSTEM_CTROL0, 0x42},  // power down

    //enable pll
    {0x3103, 0x13},

    //io direction
    {0x3017, 0xff},
    {0x3018, 0xff},

    {DRIVE_CAPABILITY, 0xc3},
    {CLOCK_POL_CONTROL, 0x21},

    {0x4713, 0x02},//jpg mode select

    {ISP_CONTROL_01, 0x83}, // turn color matrix, awb and SDE

    //sys reset
    {0x3000, 0x20}, // reset MCU
    {REG_DLY, 10}, // delay 10ms
    {0x3002, 0x1c},

    //clock enable
    {0x3004, 0xff},
    {0x3006, 0xc3},

    //bypass regular
    {0x3031,0x08},

    //isp control
    {0x5000, 0xa7},
    {ISP_CONTROL_01, 0xa3},//+scaling?
    {0x5003, 0x08},//special_effect

    //unknown
    {0x370c, 0x02},//!!IMPORTANT
    {0x3634, 0x40},//!!IMPORTANT

    //AEC/AGC
    {0x3a02, 0x03},
    {0x3a03, 0xd8},
    {0x3a08, 0x01},
    {0x3a09, 0x27},
    {0x3a0a, 0x00},
    {0x3a0b, 0xf6},
    {0x3a0d, 0x04},
    {0x3a0e, 0x03},
    {0x3a0f, 0x30},//ae_level
    {0x3a10, 0x28},//ae_level
    {0x3a11, 0x60},//ae_level
    {0x3a13, 0x43},
    {0x3a14, 0x03},
    {0x3a15, 0xd8},
    {0x3a18, 0x00},//gainceiling
    {0x3a19, 0xf8},//gainceiling
    {0x3a1b, 0x30},//ae_level
    {0x3a1e, 0x26},//ae_level
    {0x3a1f, 0x14},//ae_level

    //vcm debug
    {0x3600, 0x08},
    {0x3601, 0x33},

    //50/60Hz
    {0x3c01, 0xa4},
    {0x3c04, 0x28},
    {0x3c05, 0x98},
    {0x3c06, 0x00},
    {0x3c07, 0x08},
    {0x3c08, 0x00},
    {0x3c09, 0x1c},
    {0x3c0a, 0x9c},
    {0x3c0b, 0x40},

    {0x460c, 0x22},//disable jpeg footer

    //BLC
    {0x4001, 0x02},
    {0x4004, 0x02},

    //AWB
    {0x5180, 0xff},
    {0x5181, 0xf2},
    {0x5182, 0x00},
    {0x5183, 0x14},
    {0x5184, 0x25},
    {0x5185, 0x24},
    {0x5186, 0x09},
    {0x5187, 0x09},
    {0x5188, 0x09},
    {0x5189, 0x75},
    {0x518a, 0x54},
    {0x518b, 0xe0},
    {0x518c, 0xb2},
    {0x518d, 0x42},
    {0x518e, 0x3d},
    {0x518f, 0x56},
    {0x5190, 0x46},
    {0x5191, 0xf8},
    {0x5192, 0x04},
    {0x5193, 0x70},
    {0x5194, 0xf0},
    {0x5195, 0xf0},
    {0x5196, 0x03},
    {0x5197, 0x01},
    {0x5198, 0x04},
    {0x5199, 0x12},
    {0x519a, 0x04},
    {0x519b, 0x00},
    {0x519c, 0x06},
    {0x519d, 0x82},
    {0x519e, 0x38},

    //color matrix (Saturation)
    {0x5381, 0x1e},
    {0x5382, 0x5b},
    {0x5383, 0x08},
    {0x5384, 0x0a},
    {0x5385, 0x7e},
    {0x5386, 0x88},
    {0x5387, 0x7c},
    {0x5388, 0x6c},
    {0x5389, 0x10},
    {0x538a, 0x01},
    {0x538b, 0x98},

    //CIP control (Sharpness)
    {0x5300, 0x10},//sharpness
    {0x5301, 0x10},//sharpness
    {0x5302, 0x18},//sharpness
    {0x5303, 0x19},//sharpness
    {0x5304, 0x10},
    {0x5305, 0x10},
    {0x5306, 0x08},//denoise
    {0x5307, 0x16},
    {0x5308, 0x40},
    {0x5309, 0x10},//sharpness
    {0x530a, 0x10},//sharpness
    {0x530b, 0x04},//sharpness
    {0x530c, 0x06},//sharpness

    //GAMMA
    {0x5480, 0x01},
    {0x5481, 0x00},
    {0x5482, 0x1e},
    {0x5483, 0x3b},
    {0x5484, 0x58},
    {0x5485, 0x66},
    {0x5486, 0x71},
    {0x5487, 0x7d},
    {0x5488, 0x83},
    {0x5489, 0x8f},
    {0x548a, 0x98},
    {0x548b, 0xa6},
    {0x548c, 0xb8},
    {0x548d, 0xca},
    {0x548e, 0xd7},
    {0x548f, 0xe3},
    {0x5490, 0x1d},

    //Special Digital Effects (SDE) (UV adjust)
    {0x5580, 0x06},//enable brightness and contrast
    {0x5583, 0x40},//special_effect
    {0x5584, 0x10},//special_effect
    {0x5586, 0x20},//contrast
    {0x5587, 0x00},//brightness
    {0x5588, 0x00},//brightness
    {0x5589, 0x10},
    {0x558a, 0x00},
    {0x558b, 0xf8},
    {0x501d, 0x40},// enable manual offset of contrast

    //power on
    {0x3008, 0x02},

    //50Hz
    {0x3c00, 0x04},
    
    {REG_DLY, 300},
    {REGLIST_TAIL, 0x00}, // tail
};

重点关注这一行：

可见，这里将bit3即Bypass regulator位设置成了1，也就是说旁路（绕过）了调节器（稳压器）。笔者将此为改为0，也就是按如下代码改写后，

    //bypass regular
    //{0x3031,0x08},
    {0x3031, 0x00},

再次编译、烧录、测试，就正常了。此问题终于找到了根本原因，并完美解决！

到这里还不算完，笔者又测试了之前那几个会出现“Failed to get the frame on time”问题的OV5640摄像头，也都能够正常使用了。这就说明笔者测试的这唯一一款可用的OV5640摄像头兼容性比较好，受外部电压和内部电压供电的影响比较小。

将这个问题及解决方法也反馈给了乐鑫，大家一起涨涨经验。他们目前的库中只支持2.8V供电的，后续难保有客户使用1.8V供电，他们也表示了感谢。至此，这个问题就算是解决了。