I want to do a communication circuit, DSP and touch screen is MAX485 chip, I adopt the communication circuit as shown in figure
But now, in addition to the communication problem, MAX chip output waveform so long, there was a low level for a long period of time, do not know from where, affected the DSP receive
Please everyone a great god help, analyze, what's the problem?

CodePudding user response:

Your so-called output, it is to point to the first foot RO, MAX485 makes an impact other pins, you can't measure RO

CodePudding user response:

I measured is RO, the other foot is type A, B, and DI, I test is the place in the waveform

CodePudding user response:

refer to the second floor LINELXJ response:

is RO, I measured the other foot is type A, B, and DI, I measured it only this place appeared the waveform

You don't understand the workings of a MAX485, 485 is half duplex, you figure in the collection, the switch is sending and receiving mode, you try to test when RO waveform in the picture, what kind of collection and AB format

CodePudding user response:

My DE and AB, when DE place for delivery status, will come out this wave, if the 485 has been making for receiving state, there would be no effect

CodePudding user response:

LC1 don't need, and then three resistance resistance, around 120, should be V + to A, A - B, B - V -

CodePudding user response:

Ok, has been solved,