Uart Communication using Opto Coupler for isolating RF Controller with Metering Chip

[Mokthar]

Hi,

Iam trying to isolate uart communication between Metering mcu and RF mcu. I tried with 2 different way.

one i used Analog Digitals Digital Isolator. There is no issue while communicating with that.

Then the other using Optocoupler PC817 it works for first few cycles and there is no communication after that.

How to fine tune the opto circuit.

Schematic attached here for reference.

With Regards,
Mokthar

 

[andre_luis]

You did not mention the kind of I/O of each device:
Pushpull? Open-collector? with or w/o pullup? any circuitry connected at these nets? etc...

 

[Mokthar]

Hi Andre,

The circuitry connected with it is attached here. There are 2 circuits one with digital isolator which works fine.

Other is with opto where i have problem in communication.

On both sides i have connected with Tx and Rx pins.

With Regards,
Mokthar

 

[Easyrider83]

PC817 is a low freqency device. Maximum freqency is 80kHz. So, 9600 bps should work, more is a question.

 

[Mokthar]

PC817 is a low freqency device. Maximum freqency is 80kHz. So, 9600 bps should work, more is a question.

Here the baud rate is 4800 bps. is there i need to work out on my resistor values?

If so where did i made a mistake?

With Regards,
Mokthar