What's the best way if I want to use two microcontroller circuits?

[KKIM.6]

I need a 32-channel ADC system but my target microcontroller(STM32WB55) only has a 16-channel.

So, I want to design two microcontroller systems but the timing would be the biggest problem.

So, I wonder what's the best way to build a dual microcontroller system and how to make it communicate with each other and PC.

[Nikita91]

What are your ADC requirements: speed, how many bits...

Perhaps use external ADC instead of 2 MCU. There are some ADC chips with SPI and 8 channels.

[KKIM.6]

If I only need a larger ADC then, using a 2:1 multiplexer is enough.

But I also want to use a dual system to increase the wireless communication speed.

Is there any way recommendable?

[gregstm]

If you want to communicate between micros and PC, I guess you can't get much simpler than using a simple UART connection (just as the bootloader does). I've been using it for most things for years. If higher throughput is required, then the next thing up is an SPI interface. I only use I2C when I am forced to. Timing synchronisation could be achieved with one micro designated as the master using hardware timers. If ultimate timing precision is required between non-connected systems, then I would be looking at the Pulse-Per-Second output provided by GPS modules

[Tesla DeLorean]

Best is a very subjective term.

Not sure they'll be much support for bonding wireless comms channels.

Synchronization could come from common HSE, and some pulse or time-transfer mechanism between the two. GPS perhaps particular good for data acquisition, either using 1PPS/TIMEPULSE, but perhaps also EVENTIN/TIMEMARK type time stamping. Some receivers can generate relatively high frequencies into the 10's of MHz, although perhaps a bit too much jitter in the low-cost implementation.

[KKIM.6]

If increasing the BLE service channel, is it possible to increase data throughput?