-Use CCS

-MSP432 microcontroller

Write an assembly program to control the Red, Green, Blue LEDs on the evaluation board according to the statuses of the two switches S1 and S2.

Press only S1: RED

Press only S2: Green

Press both S1 and S2: Blue

Complete the following template to write the assembly program in Code Composer Studio. Fill in the blanks in the comments to answer the questions. Complete the missing directives, instructions, and operands accordingly. When done build the program and test it using the evaluation board.

Assembly Program Template:

Note: You must use the following program template and make it work. Failure to do so will result in a reduction of 10 points.

; Lab 6

; Setting the RGB LEDs color according to the status of the switches.

; Question 1 (Switches)

; Switch S1:

; From the evaluation board schematics determine: which I/O port and bit# ; is connected to S1, and is it connected as positive or negative logic?

; Switch S2:

; From the evaluation board schematics determine: which I/O port and bit# ; is connected to S2, and is it connected as positive or negative logic?

; (Hints: you need a pull-up resistor for negative logic input)

; Question 2 (LEDs)

; built-in red LED is connected to which I/O port and bit#?

; built-in green LED is connected to which I/O port and bit#?

; built-in blue LED is connected to which I/O port and bit#?

.thumb

.text

.align 2

; I/O mapping for I/O port x used for input

; (replace x with the correct number)

PxIN .field __________ ,32 ; Port x Input

PxOUT .field __________ ,32 ; Port x Output

PxDIR .field __________ ,32 ; Port x Direction

PxREN .field __________ ,32 ; Port x Resistor Enable

PxDS .field __________ ,32 ; Port x Drive Strength

PxSEL0 .field __________ ,32 ; Port x Select 0

PxSEL1 .field __________ ,32 ; Port x Select 1

; I/O mapping for I/O port y used for output

; (replace y with the correct number)

PyIN .field __________ ,32 ; Port y Input

PyOUT .field __________ ,32 ; Port y Output

PyDIR .field __________ ,32 ; Port y Direction

PyREN .field __________ ,32 ; Port y Resistor Enable

PyDS .field __________ ,32 ; Port y Drive Strength

PySEL0 .field __________ ,32 ; Port y Select 0

PySEL1 .field __________ ,32 ; Port y Select 1

; LED color constant

RED .equ ____ ; constant to turn Red ON

GREEN .equ ____ ; constant to turn Grn ON

BLUE .equ ____ ; constant to turn Blu ON

NONE .equ ____ ; constant to turn all OFF

; Switch status constant

SW1 .equ ____ ; input value S1 pressed

SW2 .equ ____ ; input value S2 pressed

SW12 .equ ____ ; value S1 and S2 pressed

NOSW .equ ____ ; S1 and S2 not pressed

.global main

.thumbfunc main

main: .asmfunc

BL Portx_Init BL Porty_Init

loop

BL Portx_Input ; scan S1 and S2

CMP R0, ____

BEQ sw1pressed ; switch 1 pressed

CMP R0, ____

BEQ sw2pressed ; switch 2 pressed

CMP R0, ____

BEQ bothpressed ; both switches pressed

CMP R0, ____

BEQ nonepressed ; neither switch pressed

BL Porty_Output ; Output LEDs color accordingly

B loop

sw1pressed

MOV R0, ____ ; which color should be ON?

BL Porty_Output

B loop

sw2pressed

MOV R0, ____ ; which color should be ON?

BL Porty_Output

B loop

bothpressed

MOV R0, ____ ; which color should be ON?

BL Porty_Output

B loop

nonepressed

MOV R0, ____ ; which color should be ON?

BL Porty_Output

B loop

.endasmfunc

;---------------------------------------------------------------

; Subroutine: Portx_Init (replace x with the correct port number)

; Description: Configure Px two bit# for negative logic

; input for S1 and S2 with weak internal pull-up resistors enabled.

; Input: none

; Output: none

; Modifies: R0, R1

;---------------------------------------------------------------

Portx_Init: .asmfunc

; configure Px.a and Px.b as GPIO

LDR R1, PxSEL0

LDRB R0, [R1]

____ R0, ____

STRB R0, [R1]

LDR R1, PxSEL1

LDRB R0, [R1]

____ R0, ____

STRB R0, [R1]

; make P1.4 and P1.1 inputs

LDR R1, PxDIR

LDRB R0, [R1]

____ R0, ____

STRB R0, [R1]

; enable pull resistors on both input pins

LDR R1, PxREN

LDRB R0, [R1]

____ R0, ____

STRB R0, [R1]

; Configure resistors as pull-up

LDR R1, PxOUT

LDRB R0, [R1]

____ R0, ____

STRB

; finish R0, [R1]

BX LR

.endasmfunc

;---------------------------------------------------------------

; Subroutine: Portx_Input

; Description: Read and return the status of the switches.

; Input: none

; Output: R0 0x__ Switch 1 pressed

; R0 0x__ Switch 2 pressed

; R0 0x__ Both S1 and S2 pressed

; R0 0x__ No switches are pressed

; Modifies: R1

;---------------------------------------------------------------

Portx_Input: .asmfunc

LDR R1, PxIN

LDRB R0, [R1] ; read Port x

____ R0, ____

BX LR

.endasmfunc ; extract data for S1 and S2

;---------------------------------------------------------------

; Subroutine: Porty_Init, replace y with the correct port number)

; Initialize GPIO Port y red, green, and blue LEDs

; Input: none

; Output: none

; Modifies: R0, R1

;---------------------------------------------------------------

Porty_Init: .asmfunc

; configure Port y RGB LED outputs as PGIO

LDR R1, PySEL0

LDRB R0, [R1]

____ R0, ____

STRB R0, [R1]

LDR R1, PySEL1

LDRB R0, [R1]

____ R0, ____

STRB R0, [R1]

; configure port y 3 output pins to have high-drive strength

LDR R1, PyDS

LDRB R0, [R1]

____ R0, ____

STRB R0, [R1]

; configure port y output pins as outputs

LDR R1, PyDIR

LDRB R0, [R1]

____ R0, ____

STRB R0, [R1]

; turn off Red, Grn, and Blu LEDs

LDR R1, PyOUT

LDRB R0, [R1]

____ R0, ____

STRB R0, [R1]

BX LR

.endasmfunc

;---------------------------------------------------------------

; Subroutine: Porty_Output ; Set the output state of Py.

; Input: R0 new state of Py (only 8 least significant bits)

; Output: none

; Modifies: R1

;---------------------------------------------------------------

Porty_Output: .asmfunc

LDR R1, PyOUT

____ __, _____ ; output to control LEDs

BX LR

.endasmfunc

.end