Trouble with RS-232

OpenMV Boards
1

I’m trying to receive a string from a device to the openmv H7 Plus.
In this instance I should be receiving “+01.6” - 5 ASCII characters followed by CR but instead I get the byte array b’\xd66\x9b\xe5\x80\xed\ which doesn’t translate to what I expect. Tried lowering the baud rate on both sides but similar outcome. Does OpenMV support RS-232 communication hardware wise?

#uart.init (9600, bits=8,parity=None,stop=1)
import sensor, pyb, time
from pyb import UART
import ustruct as struct


# UART 3, and baudrate.
uart = UART(3, 9600, timeout_char = 1000)

sensor.reset()
sensor.set_pixformat(sensor.GRAYSCALE)
sensor.set_framesize(sensor.QVGA)
sensor.skip_frames(time = 2000)

while(True):
    a= uart.read()
    print(a)
    time.sleep(100)
2

You can’t connect RS232 voltage levels directly to the MCU. You need a MAX232 voltage level translator. The UART should be able to receive serial TTL at 5V or 3.3V levels.

3

Thanks. Luckily I have one. I hope the board didn’t take damage that way.

4

Ok works fine. No damage to the board.