openMV和stm32单片机通讯问题

[z4l1]

就教程的串口程序，为什么单片机上显示的是乱码？

# Blob Detection and uart transport
import sensor, image, time
from pyb import UART
import json
# For color tracking to work really well you should ideally be in a very, very,
# very, controlled enviroment where the lighting is constant...
yellow_threshold   = (65, 100, -10, 6, 24, 51)
# You may need to tweak the above settings for tracking green things...
# Select an area in the Framebuffer to copy the color settings.

sensor.reset() # Initialize the camera sensor.
sensor.set_pixformat(sensor.RGB565) # use RGB565.
sensor.set_framesize(sensor.QQVGA) # use QQVGA for speed.
sensor.skip_frames(10) # Let new settings take affect.
sensor.set_auto_whitebal(False) # turn this off.
clock = time.clock() # Tracks FPS.

uart = UART(3, 115200)
def find_max(blobs):
    max_size=0
    for blob in blobs:
        if blob.pixels() > max_size:
            max_blob=blob
            max_size = blob.pixels()
    return max_blob

while(True):
    img = sensor.snapshot() # Take a picture and return the image.

    blobs = img.find_blobs([yellow_threshold])
    if blobs:
        max_blob=find_max(blobs)
        print('sum :', len(blobs))
        img.draw_rectangle(max_blob.rect())
        img.draw_cross(max_blob.cx(), max_blob.cy())

        output_str="[%d,%d]" % (max_blob.cx(),max_blob.cy()) #方式1
        #output_str=json.dumps([max_blob.cx(),max_blob.cy()]) #方式2
        print('you send:',output_str)
        uart.write(output_str+'\r\n')
    else:
        print('not found!')

[kidswong999]

貌似串口的tx,rx线有问题，要么太长，要么有干扰。建议换一个。或者波特率用9600。

建议换OpenMV配套的串口调试扩展板：

https://singtown.com/product/49906/openmv串口调试扩展板/

PS: 建议用星瞳串口助手软件：https://singtown.com/singtownserialport/

[z4l1]

@kidswong999 可以了，好像是要和单片机共地就行了，我仿佛排查就是这个原因，串口通讯需要共地才能正常传输吗？

[kidswong999]

当然，没有共地，就是没有参考电压，就没办法传输数据。