Need help with a coding assignement that needs to be completed in ARM Keil Uvision $5.$ The board I am using is an STM$32$f$4$ Discovery Board.

The Constants are given below. I have already initialized LED's, the button, Timer, and Interrupt. But please specify if you are going to change anything in the initializations.

RCC EQU $0$x$40023800$ ;base address for RCC

AHB$1$ENR EQU $0$x$30$ ;offset for this

APB$1$ENR EQU $0$x$40$ ;APB$1$ENR offset $($Clock for timer$)$

GPIOA EQU $0$x$40020000$ ;base address for PA# stuff

GPIOD EQU $0$x$40020$C$00$ ;base address for PD# stuff

MODER EQU $0$x$00$ ;mode selection register offset $($it$\text{'}$s $0)$

IDR EQU $0$x$10$ ;input data register offset from base

ODR EQU $0$x$14$ ;output data register offset from base

;NVIC Registers

NVIC$\_$ISER$0$ EQU $0$xE$000$E$100$ ;Interrupt Set$-$Enable $(0-7)$

NVIC$\_$ICER$0$ EQU $0$xE$000$E$180$ ;Interrupt Clear$-$Enable $(0-7)$

NVIC$\_$ISPR$0$ EQU $0$xE$000$E$200$ ;Interrupt Set$-$Pending $(0-7)$

NVIC$\_$ICPR$0$ EQU $0$xE$000$E$280$ ;Interrupt Clear$-$Pending $(0-7)$

NVIC$\_$IABR$0$ EQU $0$xE$000$E$300$ ;Interrupt Active Bit $(0-7)$

NVIC$\_$IPR$1$ EQU $0$xE$000$E$404$ ;Interrupt Priority $(0-59)$

STIR EQU $0$xE$000$EF$00$ ;Software Tigger Interrupt

;System Configuration Registers

SYSCFG EQU $0$x$40013800$

EXTICR$1$ EQU $0$x$08$ ;clock enables for GPIO ports

;External Interrupt Registers

EXTI EQU $0$x$40013$C$00$ ;base address

IMR EQU $0$x$00$ ;Interrupt Mask Register

EMR EQU $0$x$04$ ;Event Mask Register

RTSR EQU $0$x$08$ ;Rising Trigger Select

FTSR EQU $0$x$0$C ;Falling Trigger Select

SWIR EQU $0$x$10$ ;Software Interrupt Event

PR EQU $0$x$14$ ;Pending Register

TIM$4$EN EQU $0$x$04$ ;Timer $4$ enable $=$ bit $2$

TIM$4$ EQU $0$x$40000800$ ;Timer $4$ registers

CR$1$ EQU $0$x$00$ ;Control register $1$

DIER EQU $0$x$0$C ;DMA$/$interrupt enable register

SR EQU $0$x$10$ ;Status register

PSC EQU $0$x$28$ ;Prescaler $($offset$)$

ARR EQU $0$x$2$C ;Auto$-$Reload Register

TIM$4\_$OFF EQU $0$ ;Offset to ISER$0/$ICER$0/$ISPR$0/$ICPR$0/$IABR$0(30/32=0)$ x $4$

;prescale and Auto Reload Register are discussed in class

;Hertz $=$ cycles$/$second

;kHz $=1000,$ MHz $=1000000,$ GHz $=1000000000$

;frequency of interrupt in Hertz $=($clock frequency in Hertz$)/((1+$ARR$)(1+$PSC$))$

PSCVal EQU $3999$

ARRVal EQU $1999$