Five different frequencies, which are multiples of each other by factors of $1,1\mathrm{.}2,1\mathrm{.}4,1\mathrm{.}6,$ and $1\mathrm{.}8,$ will be generated using only one timer and will be output from different pins of a parallel port. These frequencies $($time intervals$)$ will be generated using a timer; they will not be generated using a table, and interrupts will be used for this task. Mod $1$ or mod $2$ can be used for timers.

Choose a base frequency $($time interval$)$ for this task, which can be up to $20($or $10)$ times the given frequency $($if you want finer adjustment, choose a value greater than $20$ times$).$ Create an interrupt for the base frequency $($time interval$).$ Assign a separate counter and threshold value $($two separate memory addresses for each frequency$)$ for each of the $5$ separate frequencies $($time intervals$)$ requested in the assignment. These counters will be incremented individually with the base frequency. When each of these counters reaches a threshold value, the polarity of the port pin will be changed $($logical $0$ or $1).$ Since there are $5$ different frequencies, $5$ different port pins and $2*5$ different memory areas will be used. Thus, with the interrupt taken from the base frequency, each counter will be incremented, and when the counters reach certain threshold values, the polarity of the port will be changed to obtain the frequencies requested from you $($In this case, the polarity of the port pin related to the frequency will be changed $($if it's $1,$ then $0$; if it's $0,$ then $1)).$ For each frequency, you need to find a separate threshold value considering the base frequency.

a$)$ Draw the flowchart of the algorithm.

c$)$ Write the algorithm in $8051$ machine code.