Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
I didn't use msp430 but here is a general idea, I tihnk you can easily adapt it to this controller
You can write a timer interrupt that outputs 1 from an output of MCU1 after counting for a while and resarts at the beginning of the main function. That output should be an interrupt to the MCU2 which will enable timer of MCU2. I think you can also deal with a few cycles lag by adding some null commands before restarting MCU1 timer.