Any MSP model can be used but should take care of the syntax during implementation.
Activate inbuilt peripherals like hardware interrupt and timer.
The ISR runs the code which has to be performed when the interrupt arises.
Timer ISR is used to make a precision counting of 1 second delay. This is more efficient then a for loop in a micro controller, as the CPU is not running this operation , the Timer module does.
There by saving power while the timer works in Low Power Mode.
And the output coding for 7 segment is stored in an array and called.
Can find the related material on Seconds Counter file in my repository