Fully implementation library support OV2640 camera on STM32 platform

🚀 Features

Support for resolutions:

• 160X120px,
• 320X240px,
• 640X480px,
• 800x600px,
• 1024x768px,
• 1280x960px,

Added support for extra special effects:

• brightness,
• saturation,
• contrast,
• light mode,
• special effect such as: antique, bluish, greenish, reddish, black & white style, negative, Negative with black & white style and normal view.

Support for libjpeg library. Branch with example: https://github.com/SimpleMethod/STM32-OV2640/tree/Imageoptimization

Code optimization, now requires 10 times less space in buffer than before!

📚 Documentation

The maximum size of the data buffer is 65535 bytes and this is also the maximum size of a single DCMI read. For higher resolutions, you must use the circular buffer and write own implementation in HAL_DCMI_IRQHandler. XCLX is actually the clock output from the MCU (RCC_MCO_1). The minimum speed is around 27MHz, but as high as possible is recommended for correct functioning.

Pin configuration:

PERIPHERALS	MODES	FUNCTIONS	PINS
DCMI	Slave 8 bits External Synchro	DCMI_D0	PC6
DCMI	Slave 8 bits External Synchro	DCMI_D1	PC7
DCMI	Slave 8 bits External Synchro	DCMI_D2	PC8
DCMI	Slave 8 bits External Synchro	DCMI_D3	PC9
DCMI	Slave 8 bits External Synchro	DCMI_D4	PE4
DCMI	Slave 8 bits External Synchro	DCMI_D5	PD3
DCMI	Slave 8 bits External Synchro	DCMI_D6	PE5
DCMI	Slave 8 bits External Synchro	DCMI_D7	PE6
DCMI	Slave 8 bits External Synchro	DCMI_HSYNC	PA4
DCMI	Slave 8 bits External Synchro	DCMI_PIXCLK	PA6
DCMI	Slave 8 bits External Synchro	DCMI_VSYNC	PG9
I2C1	I2C	I2C1_SCL	PB8
I2C1	I2C	I2C1_SDA	PB9
RCC	BYPASS Clock Source	RCC_OSC_IN	PH0/OSC_IN
RCC	BYPASS Clock Source	RCC_OSC_OUT	PH1/OSC_OUT
RCC	Crystal/Ceramic Resonator	RCC_OSC32_IN	PC14/OSC32_IN
RCC	Crystal/Ceramic Resonator	RCC_OSC32_OUT	PC15/OSC32_OUT
RCC	Clock-out-1	RCC_MCO_1 (DCMI_XCLX)	PA8
SYS	Serial Wire	SYS_JTCK-SWCLK	PA14
SYS	Serial Wire	SYS_JTMS-SWDIO	PA13
SYS	SysTick	SYS_VS_Systick	VP_SYS_VS_Systick
USART3	Asynchronous	USART3_RX	PD9
USART3	Asynchronous	USART3_TX	PD8
GPIO	Output	CAMERA_RESET	PG0
GPIO	Output	CAMERA_PWDN	PG1
GPIO	EXTI13	USER_Btn	PC13

DCMI configuration:

OPTION	VALUE
Pixel clock polarity	Active on Rising edge
Vertical synchronization polarity	Active Low
Horizontal synchronization polarity	Active Low
Frequency of frame capture	All frames are captured
JPEG mode	Enabled

I2C configuration:

I2C Speed Mode	Standard Mode
I2C Speed Frequency (KHz)	100
Rise Time (ns)	0
Fall Time (ns)	0
Coefficient of Digital Filter	0
Analog Filter	0
Timing	0x1060669A
Clock No Stretch Mode	Disabled
General Call Address Detection	Disabled
Primary Address Length selection	7-bit
Primary slave address	0

USART configuration:

OPTION	VALUE
Baud Rate	115200
Word Length	8 Bits(including Parity)
Parity	None
Stop Bits	1
Coefficient of Digital Filter	0
Data Direction	Receive and Transmit
Over Sampling	16 Samples
Single Sample	Disable
Auto Baudrate	Disable
TX Pin Active Level Inversion	Disable
RX Pin Active Level Inversion	Disable
Data Inversion	Disable
TX and RX Pins	Swapping
Overrun	Enable
DMA on RX Error	Enable
MSB First	Disable

DMA configuration:

DMA request	Stream	Direction	Priority
DCMI	DMA2_Stream1	PeripheralTo Memory	Very High
USART3_TX	DMA1_Stream3	Memory To Peripheral	Very High

DMA2_Stream1 DMA request settings:

OPTION	VALUE
Mode	Circular
Use fifo	Enable
FIFO Threshold	Full
Peripheral Increment	Disable
Memory Increment	Enable
Peripheral Data Width	Word
Memory Data Width	Byte
Peripheral Burst Size	Single
Memory Burst Size	Single

DMA1_Stream3 DMA request settings

OPTION	VALUE
Mode	Normal
Use fifo	Enable
FIFO Threshold	Full
Peripheral Increment	Disable
Memory Increment	Enable
Peripheral Data Width	Byte
Memory Data Width	Byte
Peripheral Burst Size	Single
Memory Burst Size	Single

NVIC configuration

Interrupt Table	Enable	Preenmption Priority	SubPriority
Non maskable interrupt	true	0	0
Hard fault interrupt	true	0	0
Memory management fault	true	0	0
Pre-fetch fault, memory access fault	true	0	0
Undefined instruction or illegal state	true	0	0
System service call via SWI instruction	true	0	0
Debug monitor	true	0	0
Pendable request for system service	true	0	0
System tick timer	true	0	0
DMA1 stream3 global interrupt	true	0	0
USART3 global interrupt	true	0	0
DMA2 stream1 global interrupt	true	0	0
DCMI global interrupt	true	0	0
PVD interrupt through EXTI line 16	unused
Flash global interrupt	unused
RCC global interrupt	unused
I2C1 event interrupt	unused
I2C1 error interrupt	unused
EXTI line[15:10]interrupts	unused
FPU global interrupt	unused

📚 Example use

1. Receive the data using a terminal or other software, default speed is set to 115200 baud.

2. Save the data dump to a file.

3. Open the file and search for the beginning of the JPEG header, it must be FFF8 value.

4. In the opened file search for the end of the data, this must be FFD9 value.

5. Open the hexadecimal editor. The example uses https://hexed.it/ and copy the data from the data dump.

6. Our data must start with FFD8 and end with FFD9.

7. Save and open the newly created file.

8. Now it's all depending on you.

💀 My code doesn't work, nothing happens, what to do?

You need to make sure that:

1. Using short connection wires , less than 10 cm (3.93 inches) - This is very, very, very important!,
2. All wires are properly connected,
3. Have a high enough clock speed for the MCU,

Use 320x240px resolution for testing - it always works :-)