Q$3$a$.[3\mathrm{.}5$ marks$]$ Write a program using an Interrupt Service Routine that does the following :

Waits for a Single High Pulse of $250ms$ on Pin OC$3.$ When the High Pulse goes from High to low $,$ it turns ON the LED at Port A$,$ RA$3$ and the LED then stays on$.$

You will use the Output Compare OC$1,$ Dual Compare mode with a Single High Pulse $004).$ You will use Timer $3$ for the OC with a pre$-$scale value of $256.$ You need to setup OC$3$RS and OC$3$R such that OC$3$RS $-OC3R=200ms.$

We need to convert $200ms$ into Timer Clock Cycles. We have Timer $3$ with a $fpb$ is $10Mhz$ and a Precale of $1$:$64.$