Problem $17$: $(35$ points$)$

In Figure $1,$ the user can tune the LED intensity through an incremental rotary encoder. This rotary encoder is designed to generate $24$ counts per revolution. Within this configuration, the dsPIC$33$EP$64$MC$502$ microcontroller monitors the rotary encoder's rotation by employing the modulo counter mode of the quadrature encoder interface module. A single complete clockwise rotation of the encoder shaft sweeps the duty cycle over its full range from $0\%$ to $100\%.$

$(5$ points$)$ Specify the peripheral pins to which the QEA and QEB are connected. Justify your answer in one or two short sentences.

$(12$ points$)$ Add the comments for lines $15,20,31,32,34,$ and $52.$

$(3$ points$)$ Determine the peripheral pin to which the LED output is connected. Justify your answer in one or two short sentences.

$(15$ points$)$ Modify the code so that two complete clockwise rotations of the encoder shaft sweep the duty cycle from $10\%$ to $80\%.$ Clearly identify the line$($s$)$ that require modification in Figure $1$ using the line number$($s$),$ and provide corresponding modified code, along with a brief justification for each change.Figure $1$: C code for Problem $17.$