Notes03:使用寄存器点亮LED_学习

Notes03:使用寄存器点亮LED

创始人

2025-05-31 01:40:37

使用寄存器点亮LED

目标

使用寄存器点亮LED_G

原理图

LED原理图

由原理图可知, LED_G阳极接3V3, 阴极接PB0, 故只需将PB0输出低电平即可点亮LED_G

打开时钟

使用RCC_APB2ENR寄存器

偏移地址
基地址

RCC的起始地址为0x4002 1000, RCC_APB2ENR的偏移地址为0x18, 故RCC_APB2ENR的绝对地址为0x4002 1000 + 0x18 = 0x4002 1018

由于我们需使用PB0所以需要打开IO端口B时钟

位说明

由图可知, 需将RCC_APB2ENR的位3置1

代码如下：

*(unsigned int *)0x40021018 |= (1 << 3); // 打开时钟, 控制RCC_APB2ENR寄存器, 实现IO端口B时钟开启/** Notes:* |= (1 << 3); // 1左移3位后相或, 即可把Bit3置位*/

配置GPIO的模式

使用GPIOx_CRL寄存器, 如下图

位说明

由于使用PB0, 所以应配置GPIOB, GPIOB的起始地址为0x4001 0C00，如下图

基地址

CRL的偏移地址为0x00， 故GPIOB_CRL的绝对地址为0x4001 0C00 + 0x00 = 0x4001 0C00

由于使用PB0, 所以需要配置端口0, 故使用CRL寄存器而非CRH寄存器, 并配置CNF0和MODE0

将PB0口配置成输出模式, 最大速度10MHz, 通用推挽输出模式， (关于GPIO原理的讲解在下节)

故MODE0 = 01, CNF0 = 00

代码如下:

*(unsigned int *)0x40010C00 |= ((1) << (4*0)); // 配置IO口为输出, 控制CRL寄存器, 实现GPIOB端口0为10MHz的推挽输出模式
/** Notes:* 分成n个一组, 对清零后的第i组设置成某二进制数, 该数对应的十进制为b* a |= (b << n * i);* 此时 |= ((1) << (4 * 0)); // 分成4个一组, 将第0组(即bit3~0)设置为1对应的二进制(即0001B)*/

PB0输出低电平

使用ODR寄存器, 如下图

位说明

由于需要使PB0输出故基地址应为GPIOB的起始地址**(即0x4001 0C00)**, 如图

基地址

故GPIOB_ODR的绝对地址为0x4001 0C00 + 0x0C = 0x4001 0C0C

因要使端口0输出低电平, 故应向ODR0 写入 0

代码如下:

*(unsigned int *)0x40010C0C &= ~(1 << 0); // 控制ODR寄存器, 实现GPIOB端口0输出低电平/** Notes:* 将变量a的Bit n位清零, a &= ~(1 << n)*/

源码

main.c文件

#include "stm32f10x.h"int main(void)
{*(unsigned int *)0x40021018 |= (1 << 3); // 打开时钟, 控制RCC_APB2ENR寄存器, 实现IO端口B时钟开启/** RCC_APB2ENR寄存器(Address : 0x40021000(RCC) + 0x18)* Bit3 : IOPBN : IO端口B时钟使能(I/O port B clock enable)* 由软件置1或请0* 0 : IO端口B时钟关闭* 1 : IO端口B时钟开启*/*(unsigned int *)0x40010C00 |= ((1) << (4*0)); // 配置IO口为输出, 控制CRL寄存器, 实现GPIOB端口0为10MHz的推挽输出模式/** GPIOx_CRL 端口配置低寄存器(Address : 0x40010C00(GPIO端口B)  + 0x00)* Bit32 CNF0 : 00 通用推挽输出模式* Bit10 MODE0 : 01 输出模式, 最大速度10MHz* * Notes:* 分成n个一组, 对清零后的第i组设置成某二进制数, 该数对应的十进制为b* a |= (b << n * i);* 此时 |= ((1) << (4 * 0)); // 分成4个一组, 将第0组(即bit3~0)设置为1对应的二进制(即0001B)*/*(unsigned int *)0x40010C0C &= ~(1 << 0); // 控制ODR寄存器, 实现GPIOB端口0输出低电平/** GPIOx_ODR 端口输出数据寄存器(Address : 0x40010C00(GPIO端口B)+ 0x0C)* Bit0 ODR0 : 端口输出数据* * Notes:* 将变量a的Bit n清零, a &= ~(1 << n);* * 注 : * 根据原理图LED_G的阳极为3V3, 阴极接PB0*/return 0;
}/** Notes:** 置位 : |= * |= (1 << 3);  // 1左移3位后相或, 把Bit3置位* * 复位 : &= ~ * &= ~(1 << 0); 1左移0位取反后相与, 把Bit0复位*/void SystemInit(void)
{return; // 编译需要
}

stm32f10x.h文件

// 用来存放STM32寄存器映射的代码
// 暂时不写

启动文件startup_stm32f10x_hd.s

;*                        SRAM mounted on STM3210E-EVAL board to be used as data 
;*                        memory (optional, to be enabled by user)
;*                      - Branches to __main in the C library (which eventually
;*                        calls main()).
;*                      After Reset the CortexM3 processor is in Thread mode,
;*                      priority is Privileged, and the Stack is set to Main.
;* <<< Use Configuration Wizard in Context Menu >>>   
;*******************************************************************************
; THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
; WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE TIME.
; AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY DIRECT,
; INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING FROM THE
; CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE CODING
; INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
;*******************************************************************************; Amount of memory (in bytes) allocated for Stack
; Tailor this value to your application needs
;  Stack Configuration
;    Stack Size (in Bytes) <0x0-0xFFFFFFFF:8>
; Stack_Size      EQU     0x00000400AREA    STACK, NOINIT, READWRITE, ALIGN=3
Stack_Mem       SPACE   Stack_Size
__initial_sp;  Heap Configuration
;     Heap Size (in Bytes) <0x0-0xFFFFFFFF:8>
; Heap_Size       EQU     0x00000200AREA    HEAP, NOINIT, READWRITE, ALIGN=3
__heap_base
Heap_Mem        SPACE   Heap_Size
__heap_limitPRESERVE8THUMB; Vector Table Mapped to Address 0 at ResetAREA    RESET, DATA, READONLYEXPORT  __VectorsEXPORT  __Vectors_EndEXPORT  __Vectors_Size__Vectors       DCD     __initial_sp               ; Top of StackDCD     Reset_Handler              ; Reset HandlerDCD     NMI_Handler                ; NMI HandlerDCD     HardFault_Handler          ; Hard Fault HandlerDCD     MemManage_Handler          ; MPU Fault HandlerDCD     BusFault_Handler           ; Bus Fault HandlerDCD     UsageFault_Handler         ; Usage Fault HandlerDCD     0                          ; ReservedDCD     0                          ; ReservedDCD     0                          ; ReservedDCD     0                          ; ReservedDCD     SVC_Handler                ; SVCall HandlerDCD     DebugMon_Handler           ; Debug Monitor HandlerDCD     0                          ; ReservedDCD     PendSV_Handler             ; PendSV HandlerDCD     SysTick_Handler            ; SysTick Handler; External InterruptsDCD     WWDG_IRQHandler            ; Window WatchdogDCD     PVD_IRQHandler             ; PVD through EXTI Line detectDCD     TAMPER_IRQHandler          ; TamperDCD     RTC_IRQHandler             ; RTCDCD     FLASH_IRQHandler           ; FlashDCD     RCC_IRQHandler             ; RCCDCD     EXTI0_IRQHandler           ; EXTI Line 0DCD     EXTI1_IRQHandler           ; EXTI Line 1DCD     EXTI2_IRQHandler           ; EXTI Line 2DCD     EXTI3_IRQHandler           ; EXTI Line 3DCD     EXTI4_IRQHandler           ; EXTI Line 4DCD     DMA1_Channel1_IRQHandler   ; DMA1 Channel 1DCD     DMA1_Channel2_IRQHandler   ; DMA1 Channel 2DCD     DMA1_Channel3_IRQHandler   ; DMA1 Channel 3DCD     DMA1_Channel4_IRQHandler   ; DMA1 Channel 4DCD     DMA1_Channel5_IRQHandler   ; DMA1 Channel 5DCD     DMA1_Channel6_IRQHandler   ; DMA1 Channel 6DCD     DMA1_Channel7_IRQHandler   ; DMA1 Channel 7DCD     ADC1_2_IRQHandler          ; ADC1 & ADC2DCD     USB_HP_CAN1_TX_IRQHandler  ; USB High Priority or CAN1 TXDCD     USB_LP_CAN1_RX0_IRQHandler ; USB Low  Priority or CAN1 RX0DCD     CAN1_RX1_IRQHandler        ; CAN1 RX1DCD     CAN1_SCE_IRQHandler        ; CAN1 SCEDCD     EXTI9_5_IRQHandler         ; EXTI Line 9..5DCD     TIM1_BRK_IRQHandler        ; TIM1 BreakDCD     TIM1_UP_IRQHandler         ; TIM1 UpdateDCD     TIM1_TRG_COM_IRQHandler    ; TIM1 Trigger and CommutationDCD     TIM1_CC_IRQHandler         ; TIM1 Capture CompareDCD     TIM2_IRQHandler            ; TIM2DCD     TIM3_IRQHandler            ; TIM3DCD     TIM4_IRQHandler            ; TIM4DCD     I2C1_EV_IRQHandler         ; I2C1 EventDCD     I2C1_ER_IRQHandler         ; I2C1 ErrorDCD     I2C2_EV_IRQHandler         ; I2C2 EventDCD     I2C2_ER_IRQHandler         ; I2C2 ErrorDCD     SPI1_IRQHandler            ; SPI1DCD     SPI2_IRQHandler            ; SPI2DCD     USART1_IRQHandler          ; USART1DCD     USART2_IRQHandler          ; USART2DCD     USART3_IRQHandler          ; USART3DCD     EXTI15_10_IRQHandler       ; EXTI Line 15..10DCD     RTCAlarm_IRQHandler        ; RTC Alarm through EXTI LineDCD     USBWakeUp_IRQHandler       ; USB Wakeup from suspendDCD     TIM8_BRK_IRQHandler        ; TIM8 BreakDCD     TIM8_UP_IRQHandler         ; TIM8 UpdateDCD     TIM8_TRG_COM_IRQHandler    ; TIM8 Trigger and CommutationDCD     TIM8_CC_IRQHandler         ; TIM8 Capture CompareDCD     ADC3_IRQHandler            ; ADC3DCD     FSMC_IRQHandler            ; FSMCDCD     SDIO_IRQHandler            ; SDIODCD     TIM5_IRQHandler            ; TIM5DCD     SPI3_IRQHandler            ; SPI3DCD     UART4_IRQHandler           ; UART4DCD     UART5_IRQHandler           ; UART5DCD     TIM6_IRQHandler            ; TIM6DCD     TIM7_IRQHandler            ; TIM7DCD     DMA2_Channel1_IRQHandler   ; DMA2 Channel1DCD     DMA2_Channel2_IRQHandler   ; DMA2 Channel2DCD     DMA2_Channel3_IRQHandler   ; DMA2 Channel3DCD     DMA2_Channel4_5_IRQHandler ; DMA2 Channel4 & Channel5
__Vectors_End__Vectors_Size  EQU  __Vectors_End - __VectorsAREA    |.text|, CODE, READONLY; Reset handler
Reset_Handler   PROCEXPORT  Reset_Handler             [WEAK]IMPORT  __mainIMPORT  SystemInitLDR     R0, =SystemInitBLX     R0               LDR     R0, =__mainBX      R0ENDP; Dummy Exception Handlers (infinite loops which can be modified)NMI_Handler     PROCEXPORT  NMI_Handler                [WEAK]B       .ENDP
HardFault_Handler\PROCEXPORT  HardFault_Handler          [WEAK]B       .ENDP
MemManage_Handler\PROCEXPORT  MemManage_Handler          [WEAK]B       .ENDP
BusFault_Handler\PROCEXPORT  BusFault_Handler           [WEAK]B       .ENDP
UsageFault_Handler\PROCEXPORT  UsageFault_Handler         [WEAK]B       .ENDP
SVC_Handler     PROCEXPORT  SVC_Handler                [WEAK]B       .ENDP
DebugMon_Handler\PROCEXPORT  DebugMon_Handler           [WEAK]B       .ENDP
PendSV_Handler  PROCEXPORT  PendSV_Handler             [WEAK]B       .ENDP
SysTick_Handler PROCEXPORT  SysTick_Handler            [WEAK]B       .ENDPDefault_Handler PROCEXPORT  WWDG_IRQHandler            [WEAK]EXPORT  PVD_IRQHandler             [WEAK]EXPORT  TAMPER_IRQHandler          [WEAK]EXPORT  RTC_IRQHandler             [WEAK]EXPORT  FLASH_IRQHandler           [WEAK]EXPORT  RCC_IRQHandler             [WEAK]EXPORT  EXTI0_IRQHandler           [WEAK]EXPORT  EXTI1_IRQHandler           [WEAK]EXPORT  EXTI2_IRQHandler           [WEAK]EXPORT  EXTI3_IRQHandler           [WEAK]EXPORT  EXTI4_IRQHandler           [WEAK]EXPORT  DMA1_Channel1_IRQHandler   [WEAK]EXPORT  DMA1_Channel2_IRQHandler   [WEAK]EXPORT  DMA1_Channel3_IRQHandler   [WEAK]EXPORT  DMA1_Channel4_IRQHandler   [WEAK]EXPORT  DMA1_Channel5_IRQHandler   [WEAK]EXPORT  DMA1_Channel6_IRQHandler   [WEAK]EXPORT  DMA1_Channel7_IRQHandler   [WEAK]EXPORT  ADC1_2_IRQHandler          [WEAK]EXPORT  USB_HP_CAN1_TX_IRQHandler  [WEAK]EXPORT  USB_LP_CAN1_RX0_IRQHandler [WEAK]EXPORT  CAN1_RX1_IRQHandler        [WEAK]EXPORT  CAN1_SCE_IRQHandler        [WEAK]EXPORT  EXTI9_5_IRQHandler         [WEAK]EXPORT  TIM1_BRK_IRQHandler        [WEAK]EXPORT  TIM1_UP_IRQHandler         [WEAK]EXPORT  TIM1_TRG_COM_IRQHandler    [WEAK]EXPORT  TIM1_CC_IRQHandler         [WEAK]EXPORT  TIM2_IRQHandler            [WEAK]EXPORT  TIM3_IRQHandler            [WEAK]EXPORT  TIM4_IRQHandler            [WEAK]EXPORT  I2C1_EV_IRQHandler         [WEAK]EXPORT  I2C1_ER_IRQHandler         [WEAK]EXPORT  I2C2_EV_IRQHandler         [WEAK]EXPORT  I2C2_ER_IRQHandler         [WEAK]EXPORT  SPI1_IRQHandler            [WEAK]EXPORT  SPI2_IRQHandler            [WEAK]EXPORT  USART1_IRQHandler          [WEAK]EXPORT  USART2_IRQHandler          [WEAK]EXPORT  USART3_IRQHandler          [WEAK]EXPORT  EXTI15_10_IRQHandler       [WEAK]EXPORT  RTCAlarm_IRQHandler        [WEAK]EXPORT  USBWakeUp_IRQHandler       [WEAK]EXPORT  TIM8_BRK_IRQHandler        [WEAK]EXPORT  TIM8_UP_IRQHandler         [WEAK]EXPORT  TIM8_TRG_COM_IRQHandler    [WEAK]EXPORT  TIM8_CC_IRQHandler         [WEAK]EXPORT  ADC3_IRQHandler            [WEAK]EXPORT  FSMC_IRQHandler            [WEAK]EXPORT  SDIO_IRQHandler            [WEAK]EXPORT  TIM5_IRQHandler            [WEAK]EXPORT  SPI3_IRQHandler            [WEAK]EXPORT  UART4_IRQHandler           [WEAK]EXPORT  UART5_IRQHandler           [WEAK]EXPORT  TIM6_IRQHandler            [WEAK]EXPORT  TIM7_IRQHandler            [WEAK]EXPORT  DMA2_Channel1_IRQHandler   [WEAK]EXPORT  DMA2_Channel2_IRQHandler   [WEAK]EXPORT  DMA2_Channel3_IRQHandler   [WEAK]EXPORT  DMA2_Channel4_5_IRQHandler [WEAK]WWDG_IRQHandler
PVD_IRQHandler
TAMPER_IRQHandler
RTC_IRQHandler
FLASH_IRQHandler
RCC_IRQHandler
EXTI0_IRQHandler
EXTI1_IRQHandler
EXTI2_IRQHandler
EXTI3_IRQHandler
EXTI4_IRQHandler
DMA1_Channel1_IRQHandler
DMA1_Channel2_IRQHandler
DMA1_Channel3_IRQHandler
DMA1_Channel4_IRQHandler
DMA1_Channel5_IRQHandler
DMA1_Channel6_IRQHandler
DMA1_Channel7_IRQHandler
ADC1_2_IRQHandler
USB_HP_CAN1_TX_IRQHandler
USB_LP_CAN1_RX0_IRQHandler
CAN1_RX1_IRQHandler
CAN1_SCE_IRQHandler
EXTI9_5_IRQHandler
TIM1_BRK_IRQHandler
TIM1_UP_IRQHandler
TIM1_TRG_COM_IRQHandler
TIM1_CC_IRQHandler
TIM2_IRQHandler
TIM3_IRQHandler
TIM4_IRQHandler
I2C1_EV_IRQHandler
I2C1_ER_IRQHandler
I2C2_EV_IRQHandler
I2C2_ER_IRQHandler
SPI1_IRQHandler
SPI2_IRQHandler
USART1_IRQHandler
USART2_IRQHandler
USART3_IRQHandler
EXTI15_10_IRQHandler
RTCAlarm_IRQHandler
USBWakeUp_IRQHandler
TIM8_BRK_IRQHandler
TIM8_UP_IRQHandler
TIM8_TRG_COM_IRQHandler
TIM8_CC_IRQHandler
ADC3_IRQHandler
FSMC_IRQHandler
SDIO_IRQHandler
TIM5_IRQHandler
SPI3_IRQHandler
UART4_IRQHandler
UART5_IRQHandler
TIM6_IRQHandler
TIM7_IRQHandler
DMA2_Channel1_IRQHandler
DMA2_Channel2_IRQHandler
DMA2_Channel3_IRQHandler
DMA2_Channel4_5_IRQHandlerB       .ENDPALIGN;*******************************************************************************
; User Stack and Heap initialization
;*******************************************************************************IF      :DEF:__MICROLIBEXPORT  __initial_spEXPORT  __heap_baseEXPORT  __heap_limitELSEIMPORT  __use_two_region_memoryEXPORT  __user_initial_stackheap__user_initial_stackheapLDR     R0, =  Heap_MemLDR     R1, =(Stack_Mem + Stack_Size)LDR     R2, = (Heap_Mem +  Heap_Size)LDR     R3, = Stack_MemBX      LRALIGNENDIFEND;******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE*****