Interrupt configured generation of a square wave signal $($pulse train of $50\%$ duty cycle$)$ on port $0$ pin $3$ is needed. The signal frequency is required to be $20$ kHz$.$ Timer $1$ will be used to generate the signal. Enable EXTERNAL INTERRUPT $1,$ as well. Assuming a $12$MHz system clock and an embedded system harboring an Intel $8051$controller$,$ with a machine cycle of $24$ system clocks:

$1.$ How often $($in seconds$)$ is the interrupt going to occur?

$2.$ Draw and show your work for programming the IE register!

$3.$ Explain what happens if $$External Interrupt $1$ comes, while Timer $1$ Interrupt Subroutine is RUNNING$.$

$4.$ Calculate the delay count and the base number Hex. Show your results in an analogy by drawing a figure and labeling it with the delay count and the base number!

$5.$ Draw and show your work for programming TL$1,$ TH$1$ and TMOD!

$6.$ Write a full assembly program fulfilling the task, by including the ORG statements of the assembler to show the $$main$$ program to start at $30$ Hex. Use the Interrupt Vector Table below.

PUT COMMENT ON EVERY CODE LINE.