嵌入式硬件 OpenMV与STM32之间的通信（附源码）

本篇文章旨在记录我电赛期间使用openmv和stm32单片机之间进行串口通信，将openmv识别到的坐标传输给单片机。背景是基于2023年全国大学生电子设计大赛E题：舵机云台追踪识别。

单片机的串口通信原理我便不再详细讲解，下面直接上代码分析。

值得注意的是接线：RX——>TX

                                 TX——>RX

                                 单片机和OPENMV必须共地

非常重要！！！！

一、串口通信传输两个数据（x坐标和y坐标） 

（一）、 OPENMV串口通信部分

import sensor, image, time,math,pyb

from pyb import UART,LED

import json

import ustruct

sensor.reset()

sensor.set_pixformat(sensor.RGB565)

sensor.set_framesize(sensor.QVGA)

sensor.skip_frames(time = 2000)

sensor.set_auto_gain(False) # must be turned off for color tracking

sensor.set_auto_whitebal(False) # must be turned off for color tracking

red_threshold_01=(10, 100, 127, 32, -43, 67)

clock = time.clock()

uart = UART(3,115200) #定义串口3变量

uart.init(115200, bits=8, parity=None, stop=1) # init with given parameters

def find_max(blobs): #定义寻找色块面积最大的函数

max_size=0

for blob in blobs:

if blob.pixels() > max_size:

max_blob=blob

max_size = blob.pixels()

return max_blob

def sending_data(cx,cy,cw,ch):

global uart;

#frame=[0x2C,18,cx%0xff,int(cx/0xff),cy%0xff,int(cy/0xff),0x5B];

#data = bytearray(frame)

data = ustruct.pack("

0x2C, #帧头1

0x12, #帧头2

int(cx), # up sample by 4 #数据1

int(cy), # up sample by 4 #数据2

int(cw), # up sample by 4 #数据1

int(ch), # up sample by 4 #数据2

0x5B)

uart.write(data); #必须要传入一个字节数组

while(True):

clock.tick()

img = sensor.snapshot()

blobs = img.find_blobs([red_threshold_01])

max_b = find_max(blobs)

cx=0;cy=0;

if blobs:

#如果找到了目标颜色

cx=max_b[5]

cy=max_b[6]

cw=max_b[2]

ch=max_b[3]

img.draw_rectangle(max_b[0:4]) # rect

img.draw_cross(max_b[5], max_b[6]) # cx, cy

FH = bytearray([0x2C,0x12,cx,cy,cw,ch,0x5B])

#sending_data(cx,cy,cw,ch)

uart.write(FH)

print(cx,cy,cw,ch)

注意观察下图标注的部分，我不做详细讲解，但是很容易理解： 

接下来请看STM32串口通信部分的代码：

#include "uart.h"

#include "oled.h"

#include "stdio.h"

static u8 Cx=0,Cy=0,Cw=0,Ch=0;

void USART1_Init(void)

{

//USART1_TX:PA 9

//USART1_RX:PA10

GPIO_InitTypeDef GPIO_InitStructure; //串口端口配置结构体变量

USART_InitTypeDef USART_InitStructure; //串口参数配置结构体变量

NVIC_InitTypeDef NVIC_InitStructure; //串口中断配置结构体变量

RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); //打开PA端口时钟

//USART1_TX PA9

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9; //PA9

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //设定IO口的输出速度为50MHz

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //复用推挽输出

GPIO_Init(GPIOA, &GPIO_InitStructure); //初始化PA9

//USART1_RX PA10

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10; //PA10

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; //浮空输入

GPIO_Init(GPIOA, &GPIO_InitStructure); //初始化PA10

//USART1 NVIC 配置

NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0 ; //抢占优先级0

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2; //子优先级2

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道使能

NVIC_Init(&NVIC_InitStructure); //根据指定的参数初始化VIC寄存器

//USART 初始化设置

USART_InitStructure.USART_BaudRate = 115200; //串口波特率为115200

USART_InitStructure.USART_WordLength = USART_WordLength_8b; //字长为8位数据格式

USART_InitStructure.USART_StopBits = USART_StopBits_1; //一个停止位

USART_InitStructure.USART_Parity = USART_Parity_No; //无奇偶校验位

USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None; //无硬件数据流控制

USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; //收发模式

USART_Init(USART1, &USART_InitStructure); //初始化串口1

USART_ITConfig(USART1, USART_IT_RXNE, ENABLE); //使能中断

USART_Cmd(USART1, ENABLE); //使能串口1

//如下语句解决第1个字节无法正确发送出去的问题

USART_ClearFlag(USART1, USART_FLAG_TC); //清串口1发送标志

}

//USART1 全局中断服务函数

void USART1_IRQHandler(void)

{

u8 com_data;

u8 i;

static u8 RxCounter1=0;

static u16 RxBuffer1[10]={0};

static u8 RxState = 0;

static u8 RxFlag1 = 0;

if( USART_GetITStatus(USART1,USART_IT_RXNE)!=RESET) //接收中断

{

USART_ClearITPendingBit(USART1,USART_IT_RXNE); //清除中断标志

com_data = USART_ReceiveData(USART1);

if(RxState==0&&com_data==0x2C) //0x2c帧头

{

RxState=1;

RxBuffer1[RxCounter1++]=com_data;OLED_Refresh();

}

else if(RxState==1&&com_data==0x12) //0x12帧头

{

RxState=2;

RxBuffer1[RxCounter1++]=com_data;

}

else if(RxState==2)

{

RxBuffer1[RxCounter1++]=com_data;

if(RxCounter1>=10||com_data == 0x5B) //RxBuffer1接受满了,接收数据结束

{

RxState=3;

RxFlag1=1;

Cx=RxBuffer1[RxCounter1-5];

Cy=RxBuffer1[RxCounter1-4];

Cw=RxBuffer1[RxCounter1-3];

Ch=RxBuffer1[RxCounter1-2];

}

}

else if(RxState==3) //检测是否接受到结束标志

{

if(RxBuffer1[RxCounter1-1] == 0x5B)

{

USART_ITConfig(USART1,USART_IT_RXNE,DISABLE);//关闭DTSABLE中断

if(RxFlag1)

{

OLED_Refresh();

OLED_ShowNum(0, 0,Cx,3,16,1);

OLED_ShowNum(0,17,Cy,3,16,1);

OLED_ShowNum(0,33,Cw,3,16,1);

OLED_ShowNum(0,49,Ch,3,16,1);

}

RxFlag1 = 0;

RxCounter1 = 0;

RxState = 0;

USART_ITConfig(USART1,USART_IT_RXNE,ENABLE);

}

else //接收错误

{

RxState = 0;

RxCounter1=0;

for(i=0;i<10;i++)

{

RxBuffer1[i]=0x00; //将存放数据数组清零

}

}

}

else //接收异常

{

RxState = 0;

RxCounter1=0;

for(i=0;i<10;i++)

{

RxBuffer1[i]=0x00; //将存放数据数组清零

}

}

}

}

注意观察下面的图：

二、串口通信传输多个数据（四个点的x、y坐标同时传输给STM32单片机）

（一）OPENMV串口部分

from machine import Pin

import sensor, image, time, pyb

#import seekfree

from pyb import UART

# 初始化TFT180屏幕

#lcd = seekfree.LCD180(3)

# 初始化摄像头

sensor.reset()

sensor.set_pixformat(sensor.RGB565) # 设置图像色彩格式为RGB565格式

sensor.set_framesize(sensor.QQVGA) # 设置图像大小为160*120

sensor.set_auto_whitebal(True) # 设置自动白平衡

sensor.set_brightness(3000) # 设置亮度为3000

sensor.skip_frames(time = 20) # 跳过帧

uart = UART(3, 115200,timeout_char=3000) #配置串口

clock = time.clock()

def sending_data(cx,cy,cw,ch):

global uart;

data = ustruct.pack("

0x2C, #帧头1

0x12, #帧头2

int (cx1), # up sample by 4 #数据26

int (cy1),

int (cx2), # up sample by 4 #数据26

int (cy2),

int (cx3), # up sample by 4 #数据26

int (cy3),

int (cx4), # up sample by 4 #数据26

int (cy4),

0x5B)

uart.write(data); #必须要传入一个字节数组

while(True):

clock.tick()

img = sensor.snapshot()

# -----矩形框部分-----

# 在图像中寻找矩形

for r in img.find_rects(threshold = 10000):

# 判断矩形边长是否符合要求

if r.w() > 20 and r.h() > 20:

# 在屏幕上框出矩形

img.draw_rectangle(r.rect(), color = (255, 0, 0), scale = 4)

# 获取矩形角点位置

corner = r.corners()

# 在屏幕上圈出矩形角点

img.draw_circle(corner[0][0], corner[0][1], 5, color = (0, 0, 255), thickness = 2, fill = False)

img.draw_circle(corner[1][0], corner[1][1], 5, color = (0, 0, 255), thickness = 2, fill = False)

img.draw_circle(corner[2][0], corner[2][1], 5, color = (0, 0, 255), thickness = 2, fill = False)

img.draw_circle(corner[3][0], corner[3][1], 5, color = (0, 0, 255), thickness = 2, fill = False)

# 打印四个角点坐标, 角点1的数组是corner[0], 坐标就是(corner[0][0],corner[0][1])

# 角点检测输出的角点排序每次不一定一致，矩形左上的角点有可能是corner0,1,2,3其中一个

corner1_str = f"corner1 = ({corner[0][0]},{corner[0][1]})"

corner2_str = f"corner2 = ({corner[1][0]},{corner[1][1]})"

corner3_str = f"corner3 = ({corner[2][0]},{corner[2][1]})"

corner4_str = f"corner4 = ({corner[3][0]},{corner[3][1]})"

print(corner1_str + "\n" + corner2_str + "\n" + corner3_str + "\n" + corner4_str)

# 显示到屏幕上，此部分会降低帧率

#lcd.show_image(img, 160, 120, 0, 0, zoom=0) #屏幕显示

#串口通信传输的数据

cx1=(int)(corner[0][0]*10)

cy1=(int)(corner[0][1]*10)

cx2=(int)(corner[1][0]*10)

cy2=(int)(corner[1][1]*10)

cx3=(int)(corner[2][0]*10)

cy3=(int)(corner[2][1]*10)

cx4=(int)(corner[3][0]*10)

cy4=(int)(corner[3][1]*10)

FH=bytearray([0x2C,0x12,cx1,cy1,cx2,cy2,cx3,cy3,cx4,cy4,0x5B])

uart.write(FH)

cx1=0

cy1=0

cx2=0

cy2=0

cx3=0

cy3=0

cx4=0

cy4=0

# 打印帧率

print(clock.fps())

下面请观察这幅代码截图：

（二）、STM32串口通信部分

#include "stm32f10x.h" // Device header

#include

#include

#include "OLED.h"

#include "LED.h"

#include "Serial.h"

uint8_t Serial_RxData;

uint8_t Serial_RxFlag;

static int16_t Cx1=0,Cy1=0,Cx2=0,Cy2=0,Cx3=0,Cy3=0,Cx4=0,Cy4=0;

int Cx5[16];//用于存放分段求的坐标值

int Cy5[16];

//static u8 RxFlag1 = 0;//串口中断接收标志位

extern float Ang1,Ang2,AngFlag;

extern float Angle1,Angle2;

int avel_X1 ;

int avel_X2 ;

int avel_X3 ;

int avel_X4 ;

int avel_Y1 ;

int avel_Y2 ;

int avel_Y3 ;

int avel_Y4 ;

void Serial_Init(void)

{

RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

//TX

GPIO_InitTypeDef GPIO_InitStructure;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_Init(GPIOB, &GPIO_InitStructure);

//RX

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_Init(GPIOB, &GPIO_InitStructure);

USART_InitTypeDef USART_InitStructure;

USART_InitStructure.USART_BaudRate = 115200;

USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;

USART_InitStructure.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;

USART_InitStructure.USART_Parity = USART_Parity_No;

USART_InitStructure.USART_StopBits = USART_StopBits_1;

USART_InitStructure.USART_WordLength = USART_WordLength_8b;

USART_Init(USART3, &USART_InitStructure);

USART_ITConfig(USART3, USART_IT_RXNE, ENABLE);

NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);

NVIC_InitTypeDef NVIC_InitStructure;

NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;

NVIC_Init(&NVIC_InitStructure);

USART_Cmd(USART3, ENABLE);

}

void Serial_SendByte(uint8_t Byte)

{

USART_SendData(USART3, Byte);

while (USART_GetFlagStatus(USART3, USART_FLAG_TXE) == RESET);

}

void Serial_SendArray(uint8_t *Array, uint16_t Length)

{

uint16_t i;

for (i = 0; i < Length; i ++)

{

Serial_SendByte(Array[i]);

}

}

void Serial_SendString(char *String)

{

uint8_t i;

for (i = 0; String[i] != '\0'; i ++)

{

Serial_SendByte(String[i]);

}

}

uint32_t Serial_Pow(uint32_t X, uint32_t Y)

{

uint32_t Result = 1;

while (Y --)

{

Result *= X;

}

return Result;

}

void Serial_SendNumber(uint32_t Number, uint8_t Length)

{

uint8_t i;

for (i = 0; i < Length; i ++)

{

Serial_SendByte(Number / Serial_Pow(10, Length - i - 1) % 10 + '0');

}

}

int fputc(int ch, FILE *f)

{

Serial_SendByte(ch);

return ch;

}

void Serial_Printf(char *format, ...)

{

char String[100];

va_list arg;

va_start(arg, format);

vsprintf(String, format, arg);

va_end(arg);

Serial_SendString(String);

}

//USART3 全局中断服务函数

void USART3_IRQHandler(void)

{

int com_data;

u8 i;

u8 Jieshou = 1;

static u8 RxCounter1=0;

static int RxBuffer1[16]={0};

static u8 RxState = 0;

static u8 RxFlag1 = 0;//串口中断接收标志位，已被移除至函数体外作为全局变量

if( USART_GetITStatus(USART3,USART_IT_RXNE)!=RESET && Jieshou == 1) //接收中断

{

// OLED_ShowSignedNum(1,1,520,4);

USART_ClearITPendingBit(USART3,USART_IT_RXNE); //清除中断标志

com_data = USART_ReceiveData(USART3);

if(Jieshou == 1)

{

if(RxState==0&&com_data==0x2C) //0x2c帧头

{

RxBuffer1[RxCounter1++]=com_data;

RxState=1;

}

else if(RxState==1&&com_data==0x12) //0x12帧头

{

RxBuffer1[RxCounter1++]=com_data;

RxState=2;

}

else if(RxState==2)

{

RxBuffer1[RxCounter1++]=com_data;

if(RxCounter1>=14||com_data == 0x5B) //RxBuffer1接受满了,接收数据结束

{

RxState=3;

RxFlag1=1;

Jieshou = 2;

Cx1=RxBuffer1[RxCounter1-9];

Cy1=RxBuffer1[RxCounter1-8];

Cx2=RxBuffer1[RxCounter1-7];

Cy2=RxBuffer1[RxCounter1-6];

Cx3=RxBuffer1[RxCounter1-5];

Cy3=RxBuffer1[RxCounter1-4];

Cx4=RxBuffer1[RxCounter1-3];

Cy4=RxBuffer1[RxCounter1-2];

OLED_ShowSignedNum(1,1,Cx1,4);

OLED_ShowSignedNum(2,1,Cy1,4);

OLED_ShowSignedNum(3,1,Cx2,4);

OLED_ShowSignedNum(4,1,Cy2,4);

OLED_ShowSignedNum(1,7,Cx3,4);

OLED_ShowSignedNum(2,7,Cy3,4);

OLED_ShowSignedNum(3,7,Cx4,4);

OLED_ShowSignedNum(4,7,Cy4,4);

}

}

}

else if(RxState==3) //检测是否接受到结束标志

{

if(RxBuffer1[RxCounter1-1] == 0x5B)

{

USART_ITConfig(USART3,USART_IT_RXNE,DISABLE);//关闭DTSABLE中断

if(RxFlag1)

{

AngFlag=0;

HuanRaoZuoBiao();

//

// OLED_ShowSignedNum(1,1,Cx1,4);

// OLED_ShowSignedNum(2,1,Cx2,4);

// OLED_ShowSignedNum(3,1,avel_X1,4);

// OLED_ShowSignedNum(4,1,Cx5[0],4);

AngFlag=1;

RxFlag1 = 0;

RxCounter1 = 0;

RxState = 0;

}

USART_ITConfig(USART3,USART_IT_RXNE,ENABLE);

}

else //接收错误

{

RxState = 0;

RxCounter1=0;

for(i=0;i<10;i++)

{

RxBuffer1[i]=0x00; //将存放数据数组清零

}

}

}

else //接收异常

{

RxState = 0;

RxCounter1=0;

for(i=0;i<10;i++)

{

RxBuffer1[i]=0x00; //将存放数据数组清零

}

}

}

}

 注意观察下面这副代码截图：

以上便是我对电赛期间OPENMV与单片机之间实现串口通信的代码实现。学者若有疑问或需要代码工程，可以私聊我。收到后我会及时回复。

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