I have pasted a link above if that does not work please see the code below to determine the blanks

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I have pasted a link above if that does not work please see the code below to determine the blanks.

GPIO_PORTD_DATA_R EQU 0x400073FC
GPIO_PORTD_DIR_R EQU 0 x40007400
GPIO_PORTD_DEN_R EQU 0 x4000751C
GPIO_PORTD_AMSEL_R EQU 0 x40007528
GPIO_PORTB_DATA_R EQU 0x400053FC
GPIO_PORTB_DIR_R EQU 0 x40005400
GPIO_PORTB_DEN_R EQU 0 x4000551C
SYSCTL_RCGCGPIO_R EQU 0 x400FE608
AREA | . t e x t | , CODE, READONLY, ALIGN=2
EXPORT main _main LDR R0 , =PortConfiguration BLX R0 LDR R1 , =GPIO_PORTD_DATA_R RunForever LDR R2 , []
STR R2 , []
B R u nFo r ev e r
P o r t C o n f i g u r a t i o n
; Po r t B i n i t i a l i z a t i o n s f i r s t
LDR R0 , =________
LDR R1 , [ R0 ]
ORR R1 , R1 , #0x02
STR R1 , [ R0 ]
NOP
NOP
NOP
NOP
LDR R0 , =GPIO_PORTB_DIR_R
LDR R1 , [ R0 ]
ORR R1 , R1 , #0x______________
STR R1 , [ R0 ]
LDR R0 , =GPIO_PORTB_DEN_R
LDR R1 , [ R0 ]
ORR R1 , R1 , #0x______________
STR R1 , [ R0 ]
; Po r t D i n i t i a l i z a t i o n s
LDR R0 , =_____
LDR R1 , [ R0 ]
ORR R1 , R1 , #0x08
STR R1 , [ R0 ]
NOP
NOP
NOP
NOP
LDR R0 , =GPIO_PORTD_DIR_R
LDR R1 , [ R0 ]
BIC R1 , R1 , #0x______________
STR R1 , [ R0 ]
LDR R0 , =GPIO_PORTD_AMSEL_R
LDR R1 , [ R0 ]
BIC R1 , R1 , #0x______________
STR R1 , [ R0 ]
LDR R0 , =GPIO_PORTD_DEN_R
LDR R1 , [ R0 ]
ORR R1 , R1 , #0x______________
STR R1 , [ R0 ]
BX LR
EXPORT S y s t e m I n i t
S y s t e m I n i t
BX LR
ALIGN
END

The Correct Answer and Explanation is :

To complete the blanks in the assembly code, understanding the role of each register and instruction is critical. Here’s the filled assembly code with explanations:

Filled Assembly Code

GPIO_PORTD_DATA_R EQU 0x400073FC
GPIO_PORTD_DIR_R EQU 0x40007400
GPIO_PORTD_DEN_R EQU 0x4000751C
GPIO_PORTD_AMSEL_R EQU 0x40007528
GPIO_PORTB_DATA_R EQU 0x400053FC
GPIO_PORTB_DIR_R EQU 0x40005400
GPIO_PORTB_DEN_R EQU 0x4000551C
SYSCTL_RCGCGPIO_R EQU 0x400FE608

AREA |.text|, CODE, READONLY, ALIGN=2
EXPORT __main
__main
    LDR R0, =PortConfiguration
    BLX R0
    LDR R1, =GPIO_PORTD_DATA_R
RunForever
    LDR R2, [R1]  ; Access GPIO_PORTD_DATA_R
    STR R2, [R1]  ; Write back to GPIO_PORTD_DATA_R
    B RunForever

PortConfiguration
    ; Port B initializations first
    LDR R0, =SYSCTL_RCGCGPIO_R  ; Enable Port B clock
    LDR R1, [R0]
    ORR R1, R1, #0x02           ; Set bit for Port B
    STR R1, [R0]
    NOP
    NOP
    NOP
    NOP
    LDR R0, =GPIO_PORTB_DIR_R   ; Configure Port B direction
    LDR R1, [R0]
    ORR R1, R1, #0x10           ; Enable pin 4 as output
    STR R1, [R0]
    LDR R0, =GPIO_PORTB_DEN_R   ; Enable digital functionality
    LDR R1, [R0]
    ORR R1, R1, #0x10           ; Enable pin 4
    STR R1, [R0]

    ; Port D initializations
    LDR R0, =SYSCTL_RCGCGPIO_R  ; Enable Port D clock
    LDR R1, [R0]
    ORR R1, R1, #0x08           ; Set bit for Port D
    STR R1, [R0]
    NOP
    NOP
    NOP
    NOP
    LDR R0, =GPIO_PORTD_DIR_R   ; Configure Port D direction
    LDR R1, [R0]
    BIC R1, R1, #0x04           ; Clear bit 2 (input)
    STR R1, [R0]
    LDR R0, =GPIO_PORTD_AMSEL_R ; Disable analog mode
    LDR R1, [R0]
    BIC R1, R1, #0x04           ; Clear bit 2 (digital mode)
    STR R1, [R0]
    LDR R0, =GPIO_PORTD_DEN_R   ; Enable digital functionality
    LDR R1, [R0]
    ORR R1, R1, #0x04           ; Enable pin 2
    STR R1, [R0]
    BX LR

EXPORT SystemInit
SystemInit
    BX LR
ALIGN
END

Explanation (300 Words)

This assembly program initializes GPIO Ports B and D of a microcontroller, enabling specific pins for input or output with digital functionality. Here’s a breakdown:

  1. Clock Enabling:
    The SYSCTL_RCGCGPIO_R register enables clocks for the GPIO ports. Each bit corresponds to a specific port (0x02 for Port B and 0x08 for Port D).
  2. Port B Configuration:
  • The direction register (GPIO_PORTB_DIR_R) is updated to set pin 4 as output (0x10).
  • The digital enable register (GPIO_PORTB_DEN_R) activates digital functionality for pin 4.
  1. Port D Configuration:
  • The direction register (GPIO_PORTD_DIR_R) configures pin 2 as input using BIC to clear the bit (0x04).
  • The analog mode select register (GPIO_PORTD_AMSEL_R) disables analog functionality on pin 2, setting it to digital mode.
  • The digital enable register (GPIO_PORTD_DEN_R) enables digital functionality for pin 2.
  1. Infinite Loop:
    The program continuously reads from and writes back to GPIO_PORTD_DATA_R. This loop can simulate monitoring or toggling.
  2. NOPs (No Operation):
    These instructions create a delay, ensuring proper synchronization during hardware operations.

Understanding this code requires knowledge of ARM assembly, GPIO registers, and microcontroller architecture. Each step modifies memory-mapped registers to control hardware behavior, showcasing how low-level programming interfaces with physical systems.

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