MCU, Multi-sensor and USB controller optimal communication setup. Need advice.

[eebhoi01]

Hi,

Once again, i am here ^_^. I suppose i'm quite familiar now.

Anyways, I would like to ask some tip about the optimal communication setup for my circuit. I have a Energy Meter IC (ADE7953), RTC, Heat sensor & MCU. I am planning to use I2C protocol for the Sensors and MCU, while UART using USB to UART chip for MCU to computer interface.

My question is this okay? in terms of practicality? I am thinking to separate the USB to PC interface from the rest of the Sensor so that it would add a bit of protection for my PC should there be some fluctuation in the high voltage side of the Energy Meter IC. By the way, can I trust the ADE7953? and omit using optocoupler (just to save some money :-D).

Also in terms of software implementation, will this setup cause future problems? To make my question more general, is it okay to implement different communication protocols (ex. I2C, SPI & UART) controlled by one MCU?

Thank you guys, as always!

 

[FvM]

I would start with designing an isolation concept for the instrument.

External interfaces (USB or UART) must be safely isolated against mains voltage, energy meter front is considerably simpler and more accurate with direct mains connection. Thus there must be an isolation barrier (class II, reinforced insulation) somewhere between energy meter chip and external interface. Processor can be placed on either the former or the latter side.

My preferred solution would be opto-coupled SPI interface for energy meter, but there are other options.