SIM_SCGC5   EQU  0x40048038 ;SIM_SCGC5 address
SIM_COPC    EQU  0x40048100 ;SIM_COPC (watchdog) address

PORTA_PCR2  EQU  0x40049008 ;PORTA_PCR2 (PTA2) address
PORTA_PCR4  EQU  0x40049010 ;PORTA_PCR4 (PTA4) address
PORTA_PCR5  EQU  0x40049014 ;PORTA_PCR5 (PTA5) address
PORTC_PCR7  EQU  0x4004B01C ;PORTA_PCR7 (PTC7) address

PORTA_PDDR  EQU 0x400FF014
PORTA_PDOR  EQU 0x400FF000
PORTC_PDDR  EQU 0x400FF094
PORTC_PDIR  EQU 0x400FF090

GREEN_MASK   EQU 0x00000004 ; PORTA_PIN 2
YELLOW_MASK  EQU 0x00000010 ; PORTA_PIN 4
RED_MASK     EQU 0x00000020 ; PORTA_PIN 5
INIT_MASKS   EQU 0x00000034 ; PORTA_PIN 2, 4 and 5
BUTTON_MASK  EQU 0X00000080 ; PORTC_PIN 7
DELAY_CNT    EQU 0X00800000

    AREA asm_area, CODE, READONLY
    EXPORT  asm_main
asm_main  ;assembly entry point for C function, do not delete
; Add program code here
    BL init_gpio
loop
    BL greenon
    LDR R0, =DELAY_CNT
    BL  delay
    BL  redon
    LDR R0, =DELAY_CNT
    BL  delay
    BL  yellowon
    LDR R0, =DELAY_CNT
    BL  delay
    B   loop
greenon
    LDR R0,=PORTA_PDOR  ;Load address of GPIOB_PCOR to R0
    LDR R1,=GREEN_MASK    ;Load value to R1
    STR R1,[R0]     ;Put value into GPIOB_PCOR
    BX LR

redon
    LDR R0,=PORTA_PDOR  ;Load address of GPIOB_PSORto R0
    LDR R1,=RED_MASK    ;Load value to R1
    STR R1,[R0]     ;Put value into GPIOB_PSOR
    BX LR

yellowon
    LDR R0,=PORTA_PDOR  ;Load address of GPIOD_PTOR to R0
    LDR R1,=YELLOW_MASK    ;Load value to R1
    STR R1,[R0] ;Put value into GPIOD_PTOR
    BX LR

delay
    SUBS R0, #1
    BNE  delay
    BX LR

init_gpio
    ;Disable watchdog timer (COP)
    LDR R0,=SIM_COPC
    LDR R1,=0x0
    STR R1,[R0]

    ;Turns on clocks for all ports
    LDR R0,=SIM_SCGC5    ;Load address of SIM_SCGC5 to R0
    LDR R1,[R0]          ;Get original value of SIM_SCGC5
    LDR R2,=0x00003E00   ;Load mask for bits to set to R2
    ORRS R1,R2           ;Set bits with OR of orig val and mask
    STR R1,[R0]          ;Put new value back into SIM_SCGC5

    ; Set PORTS to appropriate MUX settings
    LDR R0,=PORTA_PCR2   ;Load address of PORTA_PCR2 to R0
    LDR R1,=0x01    ;Load new value to R1
    STR R1,[R0]

    ; Set PORTS to appropriate MUX settings
    LDR R0,=PORTA_PCR4   ;Load address of PORTA_PCR4 to R0
    LDR R1,=0x01    ;Load new value to R1
    STR R1,[R0]

    LDR R0,=PORTA_PCR5   ;Load address of PORTA_PCR5 to R0
    LDR R1,=0x01    ;Load new value to R1
    STR R1,[R0]

    LDR R0,=PORTC_PCR7   ;Load address of PORTC_PCR7 to R0
    LDR R1,=0x01    ;Load new value to R1
    STR R1,[R0]

    ; Setup PORTA Pins 2,4 and 5 to be outputs
    LDR R0,=PORTA_PDDR   ;Load address of PORTB_PCR18 to R0
    LDR R1,=INIT_MASKS    ;Load new value to R1
    STR R1,[R0]           ;Put value into PORTB_PCR18

    ; Setup PORTC Pin 7 to be an input
    LDR R0,=PORTC_PDDR ; Load address of PORTC_PDDR to R0
    LDR R1,=BUTTON_MASK     ;Load new value to R1
    STR R1,[R0]            ;Put value into PORTC_PDDR


    BX LR

    END