When using the STM32F4 firmware library, the default crystal oscillator is a 25Mhz crystal oscillator, so some modifications need to be made. Because I had not paid attention to this problem before, I fiddled with it for a long time and found that the working clock was always wrong. After checking the information, I realized that there were several places that needed to be modified.
Original link: Modify the crystal value in the STM32 library function
The default crystal value in the STM32F407 library file is 25MHz. If the external crystal oscillator is 8MHz, the following places need to be modified:
1) Modify the value of HSE_VALUE
Will #define HSE_VALUE ((uint32_t)25000000) /*!< Value of the External oscillator in Hz */
Modify to #define HSE_VALUE ((uint32_t)8000000) /*!< Value of the External oscillator in Hz */
2) Modify the value of PLL_M
Change #define PLL_M 25 to #define PLL_M 8
3) Modify the Options settings of the STM32F407 project
In the Option for target "Flash" window, select the Target page and change the value of Xtal (MHz) in the STMicroelectronics STM32F407VG column to 8.0
Previous article：USB to serial communication in stm32f4USART
Next article：Hardware I2C of STM32F407
Recommended ReadingLatest update time:2024-11-16 19:32
stm32F4XX window watchdog HAL library
First, let’s talk about the difference between an independent watchdog and a window watchdog. Independent watchdog Iwdg——Independent of the system, because it has an independent clock, usually an external low-speed clock. Mainly used to monitor hardware errors. Window watchdog wwdg - a fault detector inside the sy
[Microcontroller]
STM32f4---Timer interrupt experimental code
Let's take a look at our time.c file. The code of the timer.c file is as follows: //General timer 3 interrupt initialization //arr: automatic reload value. psc: clock pre-division number //Timer overflow time calculation method: Tout=((arr+1)*(psc+1))/Ft us. //Ft=timer operating frequency, unit: Mhz //Timer 3 is used
[Microcontroller]
STM32F4 (read chip ID)
Unique device identifiers are suitable for: ● Used as a serial number (e.g. USB string serial number or other terminal applications) ● Use the unique ID as a security key when used in conjunction with software encryption primitives and protocols before programming the internal Flash to increase the security of the cod
[Microcontroller]
Bit counter count of stm32f432
Everyone knows that stm32f4 has rich internal resources and powerful external peripherals. It has two 32-bit counters, which is very good for many projects that need to count pulses. It not only saves the expansion of external counters and saves PCB space, but also makes program design much simpler. Since I have just
[Microcontroller]
STM32F4 ADC1 analog watchdog [library function operation]
The analog watchdog of the ADC is used to check if the voltage is out of bounds. It has two upper and lower bounds, which can be set in the registers ADC_HTR and ADC_LTR respectively. The library function is set using ADC_AnalogWatchdogThresholdsConfig, which is very simple for both regular and injected channels. When
[Microcontroller]
STM32F4 FLASH read and write operations
The STM32F407VGT6 chip used by the STM32F4Discovery development team has an internal FLASH of 1M. After the code is burned, there is still a lot of remaining. Effective use of this remaining FLASH can store a lot of data. Therefore, some operations of reading and writing the internal FLASH of STM32F4 are studied. Th
[Microcontroller]
STM32f4---OLCD display experimental code (02)
OLED_CS=1; OLED_RS=1; OLED_RST=0; delay_ms(100); OLED_RST=1; OLED_WR_Byte(0xAE,OLED_CMD); //Turn off the display OLED_WR_Byte(0xD5,OLED_CMD); //Set clock division factor, oscillation frequency OLED_WR_Byte(80,OLED_CMD); // , frequency division factor; , oscillation frequency OLED_WR_Byte(0xA8,OLED_C
[Microcontroller]
STM32F407 ADC clock setting and sampling frequency setting
/******************************************************
In system_stm32f4xx.c there are the following definitions:
/* PLL_VCO = (HSE_VALUE or HSI_VALUE / PLL_M) * PLL_N / / /
#define PLL_M 8
#define PLL_N 336
/* SYSCLK = PLL_VCO / PLL_P //
#define PLL_P 2
/* USB OTG FS, SDIO and RNG
[Microcontroller]
STM32F4 LWIP Development Manual_V2.0
GD32F4xx and STM32F4 difference document
Latest Microcontroller Articles
- Download from the Internet--ARM Getting Started NotesA brief introduction: From today on, the ARM notebook of the rookie is open, and it can be regarded as a place to store these notes. Why publish it? Maybe you are interested in it. In fact, the reason for these notes is ...
- Learn ARM development(22)Turning off and on interrupts Interrupts are an efficient dialogue mechanism, but sometimes you don't want to interrupt the program while it is running. For example, when you are printing something, the program suddenly interrupts and another ...
- Learn ARM development(21)First, declare the task pointer, because it will be used later. Task pointer volatile TASK_TCB* volatile g_pCurrentTask = NULL;volatile TASK_TCB* vol ...
- Learn ARM development(20)With the previous Tick interrupt, the basic task switching conditions are ready. However, this "easterly" is also difficult to understand. Only through continuous practice can we understand it. ...
- Learn ARM development(19)After many days of hard work, I finally got the interrupt working. But in order to allow RTOS to use timer interrupts, what kind of interrupts can be implemented in S3C44B0? There are two methods in S3C44B0. ...
- Learn ARM development(14)
- Learn ARM development(15)
- Learn ARM development(16)
- Learn ARM development(17)
He Limin Column
Microcontroller and Embedded Systems Bible
Professor at Beihang University, dedicated to promoting microcontrollers and embedded systems for over 20 years.
MoreSelected Circuit Diagrams
MorePopular Articles
- Innolux's intelligent steer-by-wire solution makes cars smarter and safer
- 8051 MCU - Parity Check
- How to efficiently balance the sensitivity of tactile sensing interfaces
- What should I do if the servo motor shakes? What causes the servo motor to shake quickly?
- 【Brushless Motor】Analysis of three-phase BLDC motor and sharing of two popular development boards
- Midea Industrial Technology's subsidiaries Clou Electronics and Hekang New Energy jointly appeared at the Munich Battery Energy Storage Exhibition and Solar Energy Exhibition
- Guoxin Sichen | Application of ferroelectric memory PB85RS2MC in power battery management, with a capacity of 2M
- Analysis of common faults of frequency converter
- In a head-on competition with Qualcomm, what kind of cockpit products has Intel come up with?
- Dalian Rongke's all-vanadium liquid flow battery energy storage equipment industrialization project has entered the sprint stage before production
MoreDaily News
- Allegro MicroSystems Introduces Advanced Magnetic and Inductive Position Sensing Solutions at Electronica 2024
- Car key in the left hand, liveness detection radar in the right hand, UWB is imperative for cars!
- After a decade of rapid development, domestic CIS has entered the market
- Aegis Dagger Battery + Thor EM-i Super Hybrid, Geely New Energy has thrown out two "king bombs"
- A brief discussion on functional safety - fault, error, and failure
- In the smart car 2.0 cycle, these core industry chains are facing major opportunities!
- The United States and Japan are developing new batteries. CATL faces challenges? How should China's new energy battery industry respond?
- Murata launches high-precision 6-axis inertial sensor for automobiles
- Ford patents pre-charge alarm to help save costs and respond to emergencies
- New real-time microcontroller system from Texas Instruments enables smarter processing in automotive and industrial applications
Guess you like
- Analog Basics: How Sample and Hold Circuits Work and Ensure ADC Accuracy
- The role of the volatile keyword
- Apple's contract factory violated the rules by using student workers, Apple responded by suspending its new business cooperation
- AD sampling average current
- Assembling a single-phase solid-state relay circuit using discrete components
- Motor Control Advanced 3——PID Cascade Control (with full code download)
- [Evaluation of domestic FPGA Gaoyun GW1N-4 series development board] ——9. Internal OSC and rPLL IP core test
- Zero-Drift Amplifiers: Features and Benefits
- Interference issues
- Help, the SD card cannot communicate normally, and the measured pin voltage is abnormal
京公网安备 11010802033920号