OpenMV与STM32之间的通信

OpenMV与STM32之间使用串口进行通信。

OpenMV

详细解释可以看代码里面的注释。
注意：转换成字节型传输时，负数会以补码形式传输，比如：-1在单片机接受时变成255.

import sensor, image, time, math#调用声明
from pyb import UART #串口

uart = UART(3, 115200, timeout_char=1000)  # i使用给定波特率初始化
uart.init(115200, bits=8, parity=None, stop=1, timeout_char=1000)
#这一行一定要写！！
#设置帧头和帧尾，便于接受方接收数据
u_start=bytearray([0xb3,0xb3])
u_over=bytearray([0x0d,0x0a])

# Camera setup...
sensor.reset() # Initialize the camera sensor.
sensor.set_pixformat(sensor.RGB565) # use grayscale.
sensor.set_framesize(sensor.QVGA) # use QQVGA for speed.
sensor.skip_frames(30) # Let new settings take affect.
sensor.set_auto_gain(False) # must be turned off for color tracking
sensor.set_auto_whitebal(False) # must be turned off for color tracking
#关闭白平衡
clock = time.clock() # Tracks FPS.


mark=([-1,-1],[-1,-1],[-1,-1])
while(True):
    times=0
    clock.tick() # Track elapsed milliseconds between snapshots().
    img = sensor.snapshot()# Take a picture and return the image.
    row_data=[0,0,0,0]
    #row_data里面存放需要返回的数据，长度可以根据需要调整
    #print(row_data)
    uart_buf = bytearray(row_data) #转换成字节型
    uart.write(u_start)	#先发帧头，再发数据，最后发帧尾
    uart.write(uart_buf)
    uart.write(u_over)
    #print(clock.fps())
   

STM32

先在项目中加入串口通信包，PA2为TXD，PA3为RXD。可以开一个串口通过串口助手打印接收到的数据。
注意：OpenMV的TXD和RXD口可以查看官网的手册，OpenMV的TXD接单片机RXD，OpenMV的RXD接单片机TXD。！！小心OpenMV给单片机反向供电，OpenMV通过数据线接电脑时务必把VCC线拔掉。！！注意共地，不然数据传不过去。
UART2.c

#include "sys.h"
#include "USART2.h"	
#include "stm32f4xx.h"

u8 USART2_RX_BUF[USART2_REC_LEN]; 
u16 USART2_RX_STA=0;   
void uart2_init(u32 bound){
   //GPIO????
  GPIO_InitTypeDef GPIO_InitStructure;
	USART_InitTypeDef USART_InitStructure;
	NVIC_InitTypeDef NVIC_InitStructure;
	
	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE); 
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2,ENABLE);
 
	//??2????????
	GPIO_PinAFConfig(GPIOA,GPIO_PinSource2,GPIO_AF_USART2); 
	GPIO_PinAFConfig(GPIOA,GPIO_PinSource3,GPIO_AF_USART2);
	
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
	GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; 
	GPIO_Init(GPIOA,&GPIO_InitStructure); //???

   //??2?????
	USART_InitStructure.USART_BaudRate = bound;//?????
	USART_InitStructure.USART_WordLength = USART_WordLength_8b;//???8?????
	USART_InitStructure.USART_StopBits = USART_StopBits_1;//?????
	USART_InitStructure.USART_Parity = USART_Parity_No;//??????
	USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//????????
	USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;	//????
  USART_Init(USART2, &USART_InitStructure); //?????2
	
	//??2 NVIC ??
  NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;//??2????
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3;//?????3
	NVIC_InitStructure.NVIC_IRQChannelSubPriority =3;		//????3
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;			//IRQ????
	NVIC_Init(&NVIC_InitStructure);	//??????????VIC???

	USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);//??????
	USART_Cmd(USART2, ENABLE);  //????1
}

void USART2_IRQHandler(void)                	//??2??????
{
	u8 Res;
	if(USART_GetITStatus(USART2, USART_IT_RXNE) != RESET)  //????(?????????0x0d  0x0a??)
	{
		Res =USART_ReceiveData(USART2);//(USART1->DR);	//????????
		
		if((USART2_RX_STA&0x8000)==0)//?????
		{
			if(USART2_RX_STA&0x4000)//????0x0d
			{
				if(Res!=0x0a)USART2_RX_STA=0;//????,????
				else USART2_RX_STA|=0x8000;	//?????
			}
			else //???0X0D
			{	
				if(Res==0x0d)USART2_RX_STA|=0x4000;
				else
				{
					USART2_RX_BUF[USART2_RX_STA&0X3FFF]=Res ;
					USART2_RX_STA++;
					if(USART2_RX_STA>(USART2_REC_LEN-1))USART2_RX_STA=0;//??????,??????
				}		 
			}
		}   		 
  } 
}

UART2.h

#ifndef __USART2_H
#define __USART2_H
#include "stdio.h"	
#include "stm32f4xx_conf.h"
#include "sys.h" 

#define USART2_REC_LEN  200 

extern u8  USART2_RX_BUF[USART2_REC_LEN]; 
extern u16 USART2_RX_STA; 
void uart2_init(u32 bound);

#endif

main.c

#include "stm32f4xx.h"
#include "usart.h"
#include "delay.h"
#include "initGPIO.h"
#include "USART2.h"	
#include "math.h"
#include "stdlib.h"
#define num_pul 1
#define move_time_ms 1
#define len_things 4
#define delay_time_ms 5
extern u16 TIM5_Flag;

 u8 row_data[200];//接受已经收到的数字；
 void get_data()//获得PA2、PA3传回的数据；
 {
		u8 t,n=0;
		u8 len=0;
	 if(USART2_RX_STA&0x8000)
		{					   
			len=USART2_RX_STA&0x3fff;
			for(t=0;t<len;t++)//检测到开头数字，并开始记录数据；
			{
				 if(USART2_RX_BUF[t]==0xb3)   
				 {
					 if(USART2_RX_BUF[t+1]==0xb3)
					 {
					    n=t+2;
						  break;
					 }
				 }
			}
			for(t=0;n<len;t++,n++)
			{
				row_data[t] = USART2_RX_BUF[n];	
        printf("row_data%d:%d  ",t+1,row_data[t]);		
			}
			printf("\r\n");
			USART2_RX_STA=0;
		}
 }

 int main(void)
{
	uart2_init(115200);
	uart_init(115200);
  while(1)
	{
		//后续操作
  }
}