Using Assembly, you write a program which utilizes the $4$x$7$ segment daughter board to implement a timer. Initially the display should read $00$:$00,$ where the left $2$ digits are seconds, and the right $2$ digits are milliseconds. When the left button $($on the daughter board$)$ is pressed, increment the timer by $1$ second. When the middle button $($on the daughter board$)$ is pressed, decrease the timer by $1$ second. When the right button $($on the daughter board$)$ is pressed, start the countdown timer. The timer should countdown in one millisecond at a time, until the timer reaches zero. When the timer reaches zero, blink the seven$-$segment display with a period of $0\mathrm{.}5$s$.$ If the left button or middle button is pressed while it is counting down, the timer should pause. The timer should not be allowed to go below zero.