使用寄存器点亮LED
目标
使用寄存器点亮LED_G
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
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
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
由于使用PB0, 所以应配置GPIOB, GPIOB的起始地址为0x4001 0C00， 如下图
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
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
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
; <h> Stack Configuration
; <o> Stack Size (in Bytes) <0x0-0xFFFFFFFF:8>
; </h>
Stack_Size EQU 0x00000400
AREA STACK, NOINIT, READWRITE, ALIGN=3
Stack_Mem SPACE Stack_Size
__initial_sp
; <h> Heap Configuration
; <o> Heap Size (in Bytes) <0x0-0xFFFFFFFF:8>
; </h>
Heap_Size EQU 0x00000200
AREA HEAP, NOINIT, READWRITE, ALIGN=3
__heap_base
Heap_Mem SPACE Heap_Size
__heap_limit
PRESERVE8
THUMB
; Vector Table Mapped to Address 0 at Reset
AREA RESET, DATA, READONLY
EXPORT __Vectors
EXPORT __Vectors_End
EXPORT __Vectors_Size
__Vectors DCD __initial_sp ; Top of Stack
DCD Reset_Handler ; Reset Handler
DCD NMI_Handler ; NMI Handler
DCD HardFault_Handler ; Hard Fault Handler
DCD MemManage_Handler ; MPU Fault Handler
DCD BusFault_Handler ; Bus Fault Handler
DCD UsageFault_Handler ; Usage Fault Handler
DCD 0 ; Reserved
DCD 0 ; Reserved
DCD 0 ; Reserved
DCD 0 ; Reserved
DCD SVC_Handler ; SVCall Handler
DCD DebugMon_Handler ; Debug Monitor Handler
DCD 0 ; Reserved
DCD PendSV_Handler ; PendSV Handler
DCD SysTick_Handler ; SysTick Handler
; External Interrupts
DCD WWDG_IRQHandler ; Window Watchdog
DCD PVD_IRQHandler ; PVD through EXTI Line detect
DCD TAMPER_IRQHandler ; Tamper
DCD RTC_IRQHandler ; RTC
DCD FLASH_IRQHandler ; Flash
DCD RCC_IRQHandler ; RCC
DCD EXTI0_IRQHandler ; EXTI Line 0
DCD EXTI1_IRQHandler ; EXTI Line 1
DCD EXTI2_IRQHandler ; EXTI Line 2
DCD EXTI3_IRQHandler ; EXTI Line 3
DCD EXTI4_IRQHandler ; EXTI Line 4
DCD DMA1_Channel1_IRQHandler ; DMA1 Channel 1
DCD DMA1_Channel2_IRQHandler ; DMA1 Channel 2
DCD DMA1_Channel3_IRQHandler ; DMA1 Channel 3
DCD DMA1_Channel4_IRQHandler ; DMA1 Channel 4
DCD DMA1_Channel5_IRQHandler ; DMA1 Channel 5
DCD DMA1_Channel6_IRQHandler ; DMA1 Channel 6
DCD DMA1_Channel7_IRQHandler ; DMA1 Channel 7
DCD ADC1_2_IRQHandler ; ADC1 & ADC2
DCD USB_HP_CAN1_TX_IRQHandler ; USB High Priority or CAN1 TX
DCD USB_LP_CAN1_RX0_IRQHandler ; USB Low Priority or CAN1 RX0
DCD CAN1_RX1_IRQHandler ; CAN1 RX1
DCD CAN1_SCE_IRQHandler ; CAN1 SCE
DCD EXTI9_5_IRQHandler ; EXTI Line 9..5
DCD TIM1_BRK_IRQHandler ; TIM1 Break
DCD TIM1_UP_IRQHandler ; TIM1 Update
DCD TIM1_TRG_COM_IRQHandler ; TIM1 Trigger and Commutation
DCD TIM1_CC_IRQHandler ; TIM1 Capture Compare
DCD TIM2_IRQHandler ; TIM2
DCD TIM3_IRQHandler ; TIM3
DCD TIM4_IRQHandler ; TIM4
DCD I2C1_EV_IRQHandler ; I2C1 Event
DCD I2C1_ER_IRQHandler ; I2C1 Error
DCD I2C2_EV_IRQHandler ; I2C2 Event
DCD I2C2_ER_IRQHandler ; I2C2 Error
DCD SPI1_IRQHandler ; SPI1
DCD SPI2_IRQHandler ; SPI2
DCD USART1_IRQHandler ; USART1
DCD USART2_IRQHandler ; USART2
DCD USART3_IRQHandler ; USART3
DCD EXTI15_10_IRQHandler ; EXTI Line 15..10
DCD RTCAlarm_IRQHandler ; RTC Alarm through EXTI Line
DCD USBWakeUp_IRQHandler ; USB Wakeup from suspend
DCD TIM8_BRK_IRQHandler ; TIM8 Break
DCD TIM8_UP_IRQHandler ; TIM8 Update
DCD TIM8_TRG_COM_IRQHandler ; TIM8 Trigger and Commutation
DCD TIM8_CC_IRQHandler ; TIM8 Capture Compare
DCD ADC3_IRQHandler ; ADC3
DCD FSMC_IRQHandler ; FSMC
DCD SDIO_IRQHandler ; SDIO
DCD TIM5_IRQHandler ; TIM5
DCD SPI3_IRQHandler ; SPI3
DCD UART4_IRQHandler ; UART4
DCD UART5_IRQHandler ; UART5
DCD TIM6_IRQHandler ; TIM6
DCD TIM7_IRQHandler ; TIM7
DCD DMA2_Channel1_IRQHandler ; DMA2 Channel1
DCD DMA2_Channel2_IRQHandler ; DMA2 Channel2
DCD DMA2_Channel3_IRQHandler ; DMA2 Channel3
DCD DMA2_Channel4_5_IRQHandler ; DMA2 Channel4 & Channel5
__Vectors_End
__Vectors_Size EQU __Vectors_End - __Vectors
AREA |.text|, CODE, READONLY
; Reset handler
Reset_Handler PROC
EXPORT Reset_Handler [WEAK]
IMPORT __main
IMPORT SystemInit
LDR R0, =SystemInit
BLX R0
LDR R0, =__main
BX R0
ENDP
; Dummy Exception Handlers (infinite loops which can be modified)
NMI_Handler PROC
EXPORT NMI_Handler [WEAK]
B .
ENDP
HardFault_Handler\
PROC
EXPORT HardFault_Handler [WEAK]
B .
ENDP
MemManage_Handler\
PROC
EXPORT MemManage_Handler [WEAK]
B .
ENDP
BusFault_Handler\
PROC
EXPORT BusFault_Handler [WEAK]
B .
ENDP
UsageFault_Handler\
PROC
EXPORT UsageFault_Handler [WEAK]
B .
ENDP
SVC_Handler PROC
EXPORT SVC_Handler [WEAK]
B .
ENDP
DebugMon_Handler\
PROC
EXPORT DebugMon_Handler [WEAK]
B .
ENDP
PendSV_Handler PROC
EXPORT PendSV_Handler [WEAK]
B .
ENDP
SysTick_Handler PROC
EXPORT SysTick_Handler [WEAK]
B .
ENDP
Default_Handler PROC
EXPORT 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_IRQHandler
B .
ENDP
ALIGN
;*******************************************************************************
; User Stack and Heap initialization
;*******************************************************************************
IF :DEF:__MICROLIB
EXPORT __initial_sp
EXPORT __heap_base
EXPORT __heap_limit
ELSE
IMPORT __use_two_region_memory
EXPORT __user_initial_stackheap
__user_initial_stackheap
LDR R0, = Heap_Mem
LDR R1, =(Stack_Mem + Stack_Size)
LDR R2, = (Heap_Mem + Heap_Size)
LDR R3, = Stack_Mem
BX LR
ALIGN
ENDIF
END
;******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE*****