Text display screen system will be designed using STM$32$ microcontroller using dot matrix LED displays. Dot matrix LED Displays' data pins are connected to $8$ bit data bus, however enable pins are independent as shown. The text that we want to display is stored in txt str$[]$ array having $7$ elements. We have a ready library function which displays characters on the dot matrix LED displays called disp char dot$($char ch$).$

a$.$ Write the code which performs this task using disp char $)$ function with interrupt method. $($Select port$/$pins as you wish$)$

b$.$ Assume we want to create sliding text display as shown. Write the code which performs this task.

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