UART isolation using Optocoupler

[vamanan]

Hi,
I am using 8051 for serial communication. It talks with another microcontroller at TTL level. So I think there is no need for MAX232. Am I correct ?. Is it enough if I connect tx of miconA to rx of moconB and rx miconA to tx of miconB. Is it like this or I need to connect some other way?. If I want to isolate this path, how can I do that?.
Regards,
Vamanan Kutty

 

[hakeen]

Hi

You can use low speed low cost couplers. You should just ensure the LED drive current and secondary side pull up resistor are OK for values given in datasheet.

I saw there is a new coupler which with very low drive current can work: ACPL-054L. You can directly drive it from many microcontrollers, as LED current can be so low as 3mA.