MAX3221E: RS232 cable connected ,the TX wave is mistake ， But Loopback is correct

user1565130

Prodigy 60 points

Part Number: MAX3221E

When I Send data from the mcu , Connect the MAX3221E Pin8 and Pin13 , the data is correct ,

When connect the board to PC , the RS232 TX is incorrect ， likely clock inferrence

the wave as below :

over 5 years ago

0 user1565130 over 5 years ago

Prodigy 60 points

interference

0 Hao L over 5 years ago in reply to user1565130

TI__Mastermind 25705 points

Hi,

Is this the data from MCU to MAX3221E? Can you compare the waveform with and without loop back? Similarly can you check the bus signal level with and without loop back? RS232 signal should be around -5V to 5V. What's data rate of the application?

Regards,

Hao

Interface

Interface forum

MAX3221E: RS232 cable connected ,the TX wave is mistake ， But Loopback is correct