1, STM32CubeMX generated code
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Download and install STM32CubeMX , after opening, the interface is as follows. Click help to download the dependent package
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Select the package corresponding to your board. There is no problem with different versions. After downloading, the check box in front will turn green
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Create a new project
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Enter your own chip in part name. Take STMC8T6 as an example. Then a column of information will appear. Click and then click start project
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Click System Core, enter SYS, and select Serial Wire in debug
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Enter the rcc above and set the hse as Crystal/Ceramic Resonator
Select pllclk in the clock configuration
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GPIO sets the output register, finds PA7, PB9 and PC15, selects output, and sets the output level to high
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Click project manager, configure your own path and project name, and then change the IDE item to MDK-ARM
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Enter the code generate interface, select generate initialization. c/.h file, and then click generate code
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The project file has been automatically generated under the corresponding path
2, keil simulates debugging and generates hex files
- keil opens the project file and finds the main function
- Modify main function code (HAL Library)
SystemClock_Config();//System clock initialization MX_GPIO_Init();//gpio initialization while (1) { HAL_GPIO_WritePin(GPIOA,GPIO_PIN_7,GPIO_PIN_RESET);//PA7 on HAL_Delay(500);//Delay 0.5s HAL_GPIO_WritePin(GPIOA,GPIO_PIN_7,GPIO_PIN_SET);//PA7 lights out HAL_Delay(500);//Delay 0.5s HAL_GPIO_WritePin(GPIOB,GPIO_PIN_9,GPIO_PIN_RESET);//PB9 on HAL_Delay(500);//Delay 0.5s HAL_GPIO_WritePin(GPIOB,GPIO_PIN_9,GPIO_PIN_SET);//PB9 lights out HAL_Delay(500);//Delay 0.5s HAL_GPIO_WritePin(GPIOC,GPIO_PIN_15,GPIO_PIN_RESET);//PC15 on HAL_Delay(500);//Delay 0.5s HAL_GPIO_WritePin(GPIOC,GPIO_PIN_15,GPIO_PIN_SET);//PC15 lights out HAL_Delay(500);//Delay 0.5s }
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Burning operation , the serial port burning can operate normally only after the power is off and the boot0 is set to 0
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Simulation debugging , enter logic analysis
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Set the logical analysis, add three ports: porta.7, portb.9 and portc.15, and change the display type to bit
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Click run to start operation and check the waveform diagram. You can see that there is only one low level each time and the duration is 0.5s. After a delay of 0.5s, the next low level appears, one cycle every 3s
3, Serial communication
- USART introduction
Universal synchronous asynchronous receiver and transmitter is a serial communication device, which can flexibly exchange full duplex data with external devices. Different from USART, there is also a UART(Universal Asynchronous Receiver and Transmitter), which cuts out the synchronous communication function on the basis of USART, and only asynchronous communication. The simple distinction between synchronous and asynchronous is to see whether the clock output needs to be provided during communication. The serial port communication we usually use is basically UART.
Serial communication generally transmits data in frame format, that is, frame by frame transmission. Each frame contains start signal, data information, stop information and possibly verification information. USART has specific provisions on these transmission parameters. Of course, there is not only one parameter value. Many parameter values can be customized to enhance its compatibility. - Create a new project and select f103 chip without checking CORE and Startup
- Create a new hello.s file and fill in the code
;RCC Register address mapping RCC_BASE EQU 0x40021000 RCC_CR EQU (RCC_BASE + 0x00) RCC_CFGR EQU (RCC_BASE + 0x04) RCC_CIR EQU (RCC_BASE + 0x08) RCC_APB2RSTR EQU (RCC_BASE + 0x0C) RCC_APB1RSTR EQU (RCC_BASE + 0x10) RCC_AHBENR EQU (RCC_BASE + 0x14) RCC_APB2ENR EQU (RCC_BASE + 0x18) RCC_APB1ENR EQU (RCC_BASE + 0x1C) RCC_BDCR EQU (RCC_BASE + 0x20) RCC_CSR EQU (RCC_BASE + 0x24) ;AFIO Register address mapping AFIO_BASE EQU 0x40010000 AFIO_EVCR EQU (AFIO_BASE + 0x00) AFIO_MAPR EQU (AFIO_BASE + 0x04) AFIO_EXTICR1 EQU (AFIO_BASE + 0x08) AFIO_EXTICR2 EQU (AFIO_BASE + 0x0C) AFIO_EXTICR3 EQU (AFIO_BASE + 0x10) AFIO_EXTICR4 EQU (AFIO_BASE + 0x14) ;GPIOA Register address mapping GPIOA_BASE EQU 0x40010800 GPIOA_CRL EQU (GPIOA_BASE + 0x00) GPIOA_CRH EQU (GPIOA_BASE + 0x04) GPIOA_IDR EQU (GPIOA_BASE + 0x08) GPIOA_ODR EQU (GPIOA_BASE + 0x0C) GPIOA_BSRR EQU (GPIOA_BASE + 0x10) GPIOA_BRR EQU (GPIOA_BASE + 0x14) GPIOA_LCKR EQU (GPIOA_BASE + 0x18) ;GPIO C Mouth control GPIOC_BASE EQU 0x40011000 GPIOC_CRL EQU (GPIOC_BASE + 0x00) GPIOC_CRH EQU (GPIOC_BASE + 0x04) GPIOC_IDR EQU (GPIOC_BASE + 0x08) GPIOC_ODR EQU (GPIOC_BASE + 0x0C) GPIOC_BSRR EQU (GPIOC_BASE + 0x10) GPIOC_BRR EQU (GPIOC_BASE + 0x14) GPIOC_LCKR EQU (GPIOC_BASE + 0x18) ;Serial port 1 control USART1_BASE EQU 0x40013800 USART1_SR EQU (USART1_BASE + 0x00) USART1_DR EQU (USART1_BASE + 0x04) USART1_BRR EQU (USART1_BASE + 0x08) USART1_CR1 EQU (USART1_BASE + 0x0c) USART1_CR2 EQU (USART1_BASE + 0x10) USART1_CR3 EQU (USART1_BASE + 0x14) USART1_GTPR EQU (USART1_BASE + 0x18) ;NVIC Register address NVIC_BASE EQU 0xE000E000 NVIC_SETEN EQU (NVIC_BASE + 0x0010) ;SETENA Starting address of register array NVIC_IRQPRI EQU (NVIC_BASE + 0x0400) ;Start address of interrupt priority register array NVIC_VECTTBL EQU (NVIC_BASE + 0x0D08) ;Address of vector table offset register NVIC_AIRCR EQU (NVIC_BASE + 0x0D0C) ;Address of application interrupt and reset control register SETENA0 EQU 0xE000E100 SETENA1 EQU 0xE000E104 ;SysTick Register address SysTick_BASE EQU 0xE000E010 SYSTICKCSR EQU (SysTick_BASE + 0x00) SYSTICKRVR EQU (SysTick_BASE + 0x04) ;FLASH Buffer register address image FLASH_ACR EQU 0x40022000 ;SCB_BASE EQU (SCS_BASE + 0x0D00) MSP_TOP EQU 0x20005000 ;Starting value of main stack PSP_TOP EQU 0x20004E00 ;Process stack start value BitAlias_BASE EQU 0x22000000 ;Bit alias area start address Flag1 EQU 0x20000200 b_flas EQU (BitAlias_BASE + (0x200*32) + (0*4)) ;Bit address b_05s EQU (BitAlias_BASE + (0x200*32) + (1*4)) ;Bit address DlyI EQU 0x20000204 DlyJ EQU 0x20000208 DlyK EQU 0x2000020C SysTim EQU 0x20000210 ;Constant definition Bit0 EQU 0x00000001 Bit1 EQU 0x00000002 Bit2 EQU 0x00000004 Bit3 EQU 0x00000008 Bit4 EQU 0x00000010 Bit5 EQU 0x00000020 Bit6 EQU 0x00000040 Bit7 EQU 0x00000080 Bit8 EQU 0x00000100 Bit9 EQU 0x00000200 Bit10 EQU 0x00000400 Bit11 EQU 0x00000800 Bit12 EQU 0x00001000 Bit13 EQU 0x00002000 Bit14 EQU 0x00004000 Bit15 EQU 0x00008000 Bit16 EQU 0x00010000 Bit17 EQU 0x00020000 Bit18 EQU 0x00040000 Bit19 EQU 0x00080000 Bit20 EQU 0x00100000 Bit21 EQU 0x00200000 Bit22 EQU 0x00400000 Bit23 EQU 0x00800000 Bit24 EQU 0x01000000 Bit25 EQU 0x02000000 Bit26 EQU 0x04000000 Bit27 EQU 0x08000000 Bit28 EQU 0x10000000 Bit29 EQU 0x20000000 Bit30 EQU 0x40000000 Bit31 EQU 0x80000000 ;Vector table AREA RESET, DATA, READONLY DCD MSP_TOP ;Initialize main stack DCD Start ;Reset vector DCD NMI_Handler ;NMI Handler DCD HardFault_Handler ;Hard Fault Handler DCD 0 DCD 0 DCD 0 DCD 0 DCD 0 DCD 0 DCD 0 DCD 0 DCD 0 DCD 0 DCD 0 DCD SysTick_Handler ;SysTick Handler SPACE 20 ;Reserved space 20 bytes ;Code snippet AREA |.text|, CODE, READONLY ;Main program start ENTRY ;Instructs the program to execute from here Start ;Clock system settings ldr r0, =RCC_CR ldr r1, [r0] orr r1, #Bit16 str r1, [r0] ;Enable external crystal oscillator ;Start external 8 M Crystal oscillator ClkOk ldr r1, [r0] ands r1, #Bit17 beq ClkOk ;Wait for the external crystal oscillator to be ready ldr r1,[r0] orr r1,#Bit17 str r1,[r0] ;FLASH Buffer ldr r0, =FLASH_ACR mov r1, #0x00000032 str r1, [r0] ;set up PLL The PLL magnification is 7,HSE Input no frequency division ldr r0, =RCC_CFGR ldr r1, [r0] orr r1, #(Bit18 :OR: Bit19 :OR: Bit20 :OR: Bit16 :OR: Bit14) orr r1, #Bit10 str r1, [r0] ;start-up PLL Phase locked loop ldr r0, =RCC_CR ldr r1, [r0] orr r1, #Bit24 str r1, [r0] PllOk ldr r1, [r0] ands r1, #Bit25 beq PllOk ;choice PLL Clock as system clock ldr r0, =RCC_CFGR ldr r1, [r0] orr r1, #(Bit18 :OR: Bit19 :OR: Bit20 :OR: Bit16 :OR: Bit14) orr r1, #Bit10 orr r1, #Bit1 str r1, [r0] ;other RCC Related settings ldr r0, =RCC_APB2ENR mov r1, #(Bit14 :OR: Bit4 :OR: Bit2) str r1, [r0] ;PA9 Serial port 0 transmitting pin ldr r0, =GPIOA_CRH ldr r1, [r0] orr r1, #(Bit4 :OR: Bit5) ;PA.9 Output mode,Maximum speed 50 MHz orr r1, #Bit7 and r1, #~Bit6 ;10: Multiplexing function push-pull output mode str r1, [r0] ldr r0, =USART1_BRR mov r1, #0x271 str r1, [r0] ;Configure baud rate-> 115200 ldr r0, =USART1_CR1 mov r1, #0x200c str r1, [r0] ;USART Module total enable send and receive enable ;71 02 00 00 2c 20 00 00 ;AFIO Parameter setting ;Systick Parameter setting ldr r0, =SYSTICKRVR ;Systick Initial installation value mov r1, #9000 str r1, [r0] ldr r0, =SYSTICKCSR ;set up,start-up Systick mov r1, #0x03 str r1, [r0] ;Switch to user level line program mode ldr r0, =PSP_TOP ;Initialize thread stack msr psp, r0 mov r0, #3 msr control, r0 ;initialization SRAM register mov r1, #0 ldr r0, =Flag1 str r1, [r0] ldr r0, =DlyI str r1, [r0] ldr r0, =DlyJ str r1, [r0] ldr r0, =DlyK str r1, [r0] ldr r0, =SysTim str r1, [r0] ;Main cycle main ldr r0, =Flag1 ldr r1, [r0] tst r1, #Bit1 ;SysTick Generate 0.5s,Set bit 1 beq main ;0.5s The flag is not set yet ;0.5s The flag has been set ldr r0, =b_05s ;Bit band operation reset 0.5s sign mov r1, #0 str r1, [r0] mov r0, #'H' bl send_a_char mov r0, #'e' bl send_a_char mov r0, #'l' bl send_a_char mov r0, #'l' bl send_a_char mov r0, #'o' bl send_a_char mov r0, #' ' bl send_a_char mov r0, #'W' bl send_a_char mov r0, #'o' bl send_a_char mov r0, #'r' bl send_a_char mov r0, #'l' bl send_a_char mov r0, #'d' bl send_a_char mov r0, #'\n' bl send_a_char b main ;Subroutine serial port 1 sends a character send_a_char push {r0 - r3} ldr r2, =USART1_DR str r0, [r2] b1 ldr r2, =USART1_SR ldr r2, [r2] tst r2, #0x40 beq b1 ;Send complete(Transmission complete)wait for pop {r0 - r3} bx lr ;Abnormal program NMI_Handler bx lr HardFault_Handler bx lr SysTick_Handler ldr r0, =SysTim ldr r1, [r0] add r1, #1 str r1, [r0] cmp r1, #500 bcc TickExit mov r1, #0 str r1, [r0] ldr r0, =b_05s ;The clock tick counter is set to 0 when it is greater than or equal to 500 times of clearing.5s Flag bit ;Bit band operation set 1 mov r1, #1 str r1, [r0] TickExit bx lr ALIGN ;By using zero or null instructions NOP fill,Aligns the current position with a specified boundary END
- Burning operation
- Open logical analysis and add USART1_SR
- Observe the waveform, and there will be a fluctuation every other period of time, which is consistent with the periodic output
4, Summary
The implementation of led water lamp is still very simple. Initialize the pins that need to be used to periodically output high and low levels. Send information to the computer through the serial port. First initialize the pins to be used. After the program is entered, it will periodically send data to the computer through usart when powered on.
reference resources
Using stmsubemx to generate code (using hal Library) to implement water lamp
STM32 communicates through serial port (assembly)