EMC of TMS470 vs Silabs F236

[korobov_michael]

silabs f236

Dear friends!
I have a question for all of you.
Recently I made a project which includes the Silabs’ MCU C8051F236. This MCU serves as control unit – it controls powerful relays. I observed that the MCU is not reliable during commutation moments – it may hang-up and even switching the RESET pin to GND doesn’t help (I had to switching power off). (Answering to the possible questions – all electro-magnetic influences were eliminated and the PCB was made by high-class specialist – problems were encountered exactly with this series of MCU).
Now I’d like to try TMS470 MCUs. Tell me please if there are problems with this MCUs with their EMC (during switching the relays etc.). Thank you!

 

[XNOX_Rambo]

tms470 emc reset

Some time ago I solved a similar problem involving a PIC that was switching relays.
There were two problems - the PIC went into latch-up due to the commutation
disturbance and then was unable to recover from the latch-up due to a bad design
of the power supply.
I corrected the power supply and improved the noise immunity of the PIC and
the design is impossible to disturb now.
So my suggestion to you is to first check the power supply design.

If you could post the schematics and PCB layout I could have a look at it.
Or mail it, if it is confidential...