Objective of this lab:

	To explore STM32 value line Discovery Board  peripheral devices.

Preparation

	Read lab lecture notes.

Lab Assignment

Assignment: To be marked in lab

Procedures:

• Get to know more about STM32VLDISCOVERY BOARD from the provided info.
• Read the given program and try to understand it as much as possible.
• Create a new project in the Keil uVision 5 with the given program below.
• Complete the given program so that when the user push botton is pressed, the LEDs (BLUE and GREEN) are blinking, meaning BLUE and GREEN LEDs are on and off alternatively. Otherwise, both BLUE and GREEN LEDs are off.

The given program:

; GPIO Test program - Dave Duguid, 2011
; Adapted by Guili Liu in November 2014

;;; Directives
            PRESERVE8
            THUMB       

;;; Equates

INITIAL_MSP	EQU		0x20001000	; Initial Main Stack Pointer Value

;The offboard DIP Switch will be on port A bits 0 thru 3
;PORT A GPIO - Base Addr: 0x40010800 
GPIOA_CRL	EQU		0x40010800	; (0x00) Port Configuration Register for Px7 -> Px0
;GPIOA_CRH	EQU		0x40010804	; (0x04) Port Configuration Register for Px15 -> Px8
GPIOA_IDR	EQU		0x40010808	; (0x08) Port Input Data Register
;GPIOA_ODR	EQU		0x4001080C	; (0x0C) Port Output Data Register
GPIOA_BSRR	EQU		0x40010810	; (0x10) Port Bit Set/Reset Register
GPIOA_BRR	EQU		0x40010814	; (0x14) Port Bit Reset Register
GPIOA_LCKR	EQU		0x40010818	; (0x18) Port Configuration Lock Register

;The onboard LEDS are on port C bits 8 and 9
;PORT C GPIO - Base Addr: 0x40011000
;GPIOC_CRL	EQU		0x40011000	; (0x00) Port Configuration Register for Px7 -> Px0
GPIOC_CRH	EQU		0x40011004	; (0x04) Port Configuration Register for Px15 -> Px8
;GPIOC_IDR	EQU		0x40011008	; (0x08) Port Input Data Register
GPIOC_ODR	EQU		0x4001100C	; (0x0C) Port Output Data Register
GPIOC_BSRR	EQU		0x40011010	; (0x10) Port Bit Set/Reset Register
;GPIOC_BRR	EQU		0x40011014	; (0x14) Port Bit Reset Register
;GPIOC_LCKR	EQU		0x40011018	; (0x18) Port Configuration Lock Register

;Registers for configuring and enabling the clocks
;RCC Registers - Base Addr: 0x40021000
;RCC_CR		EQU		0x40021000	; Clock Control Register
;RCC_CFGR	EQU		0x40021004	; Clock Configuration Register
;RCC_CIR	EQU		0x40021008	; Clock Interrupt Register
;RCC_APB2RSTR	EQU		0x4002100C	; APB2 Peripheral Reset Register
;RCC_APB1RSTR	EQU		0x40021010	; APB1 Peripheral Reset Register
;RCC_AHBENR	EQU		0x40021014	; AHB Peripheral Clock Enable Register
RCC_APB2ENR	EQU		0x40021018	; APB2 Peripheral Clock Enable Register
;RCC_APB1ENR	EQU		0x4002101C	; APB1 Peripheral Clock Enable Register
;RCC_BDCR	EQU		0x40021020	; Backup Domain Control Register
;RCC_CSR	EQU		0x40021024	; Control/Status Register
;RCC_CFGR2	EQU		0x4002102C	; Clock Configuration Register 2

; Times for delay routines
        
DELAYTIME	EQU		1600000		; (200 ms/24MHz PLL)
;DELAYTIME	EQU		160000		; (20 ms/24MHz PLL)
;DELAYTIME	EQU		16000		; (2 ms/24MHz PLL)
;DELAYTIME	EQU		800000		; (100 ms/24MHz PLL)
;DELAYTIME	EQU		80000		; (10 ms/24MHz PLL)
;DELAYTIME	EQU		8000		; (1 ms/24MHz PLL)

; Vector Table Mapped to Address 0 at Reset
            AREA    RESET, Data, READONLY
            EXPORT  __Vectors

__Vectors	DCD		INITIAL_MSP		; stack pointer value when stack is empty
        	DCD		Reset_Handler		; reset vector
        	
			
            AREA    MYCODE, CODE, READONLY
			EXPORT	Reset_Handler
			ENTRY

Reset_Handler		
		
		;; Enable peripheral clocks for various ports and subsystems
		; Bit 4: Port C, Bit 3: Port B, Bit 2: Port A
gpio_clk_ena
		ldr		R6, = RCC_APB2ENR	; R6 is pointer to register
		mov		R0, #0x001C		; To turn on clocks for Ports A through C
		str		R0, [R6]		; Turn on clocks for Ports A through C

gpio_init
		;; Set the config and mode bits for Port A bits 0 through 3 to
		;; Floating Input

		ldr		R6, = GPIOA_CRL
		ldr		R0, = 0x44444444	; CNF: 01, Mode: 00
		str		R0, [R6]

		        
		;; Set the config and mode bits for Port C bit 9/8 so they will
		;; be push-pull outputs (up to 50 MHz)

		ldr		R6, = GPIOC_CRH
		ldr		R0, = 0x44444433	; CNF: 00, Mode: 11
		str		R0, [R6]

		;; Load R2 and R3 with the "on" and "off" constants
		;mov		R2, #0x0100         ; To turn PC8 on (STM DISCOVERY)
		;mov		R3, #0x0200         ; To turn PC9 on (STM DISCOVERY)


		ALIGN
					
        
main		

		mov     R0, #0x0000
			
Wait_For_Input
			
		LDR  R8, = GPIOA_IDR	;Port A Input Data Register
			
		1. Read the input from Port A

		2. Check if the bit 0 is 1, 
		   if yes, branch to   BlueGreenBlink
			otherwise branch to   Wait_For_Input
			
BlueGreenBlink			
		1.  Set PC8 only, turn on BLUE LED
			
		2.  Delay
			
		3.  Set PC9 only, turn on GREEN LED
		
		4.  Delay
			
		5.  Turn both LEDs off
						
		b		main

		ALIGN
			
	
delay		PROC
	
		6. Complete the delay procedure

		ALIGN
		ENDP
			
			     
		ALIGN
		
		END                  

This page last modified: Friday, 21-Aug-2020 15:22:38 CST

Accessed     times.