Analysis of the Causes of Single Chip Microcomputer Clock Error-EEWORLD

Collect

1. The timing pulse reference of the single-chip microcomputer electronic clock is provided by the frequency of the external crystal oscillator after 12 divisions, and the internal timing and counter are used to realize the timing function. Therefore, the accuracy of the external crystal oscillator frequency directly affects the accuracy of the electronic clock timing.

2. The electronic clock of the single-chip microcomputer uses internal timing, counter overflow to generate an interrupt (12MHz crystal oscillator is generally 50ms) and then multiply it by the corresponding multiple to realize the conversion of seconds, minutes and hours. As we all know, it takes 3-8 machine cycles from the timing and counter generating an interrupt request to responding to the interrupt. The data stack in the timing interrupt subroutine and the initial value of the timing and counter also take several machine cycles. In addition, it also takes a certain machine cycle to switch from the interrupt population to the interrupt subroutine. For example:

From the above program, it can be seen that it takes 2+2+2=6 machine cycles to load the lower 8 bits from the interrupt population to the initial value of the timer/counter. Therefore, these 6 machine cycles are generally added to the initial value of the timer/counter during programming. However, it takes several machine cycles (3~8 machine cycles) from the timer/counter overflow interrupt request to the execution of the interrupt. It is difficult to determine the exact value, which is the reason why the electronic clock timing is inaccurate.

Keywords：MCU Reference address：Analysis of the Causes of Single Chip Microcomputer Clock Error

Previous article：Solution to MCU clock error
Next article：Two common negative voltage generating circuits in single chip microcomputer electronic circuits

Recommended ReadingLatest update time:2024-11-16 14:52

51 single chip microcomputer and TA8435 stepper motor subdivision control

1 Stepper motor Stepper motor is a pure digital control motor. It converts electrical pulse signal into angular displacement. That is, when a pulse is given, the stepper motor rotates an angle. Therefore, it is very suitable for single-chip microcomputer control. Under non-overload conditions, the motor speed an

[Microcontroller]

51 single chip microcomputer and TA8435 stepper motor subdivision control

[51 MCU STC89C52] Use of LCD1602 LCD screen

1. LCD1602 module 1. Pin description Pin 3: VL is the contrast adjustment terminal of the LCD. The contrast is the weakest when connected to the positive power supply, and the contrast is the highest when connected to the ground. If it is too high, "ghosting" will occur. The contrast can be adjusted through a 10K p

[Microcontroller]

[51 MCU STC89C52] Use of LCD1602 LCD screen

51 MCU serial port operation entry experience summary and C source code

It feels good to use a computer to control a microcontroller, and then control other peripherals such as relays. How to achieve it? Let's do it step by step. To realize the microcontroller serial port communication, that is, the communication between the microcontroller and the computer, you need to understand some ba

[Microcontroller]

Liujing MCU Bidirectional Thyristor Interface MDK160

The most convenient way to control industrial frequency AC power with a single chip microcomputer is to use a bidirectional thyristor MDK160A. In order to avoid the interference and influence on the power supply caused by the impact current generated when the thyristor is turned on, MDK160A can use zero-crossing trigg

[Microcontroller]

Liujing MCU Bidirectional Thyristor Interface MDK160

PIC microcontroller internal power-off lock reset

　　1. Design ideas 　　In the single-chip microcomputer application system, if dry batteries or rechargeable batteries are used for power supply, there is a problem of continuous battery voltage drop. If AC power is used for power supply, there are problems of voltage fluctuation and power supply interference. 　　The in

[Microcontroller]

51 MCU driving capability (source current_sink current) and pull-up resistor

It seems that many netizens are confused about the concepts of sink current and source current. Let me explain this below. I hope that you will not be troubled by this after reading this article. An important premise: sink current and source current are for ports. Glossary - Sink: inject, fill, from outs

[Microcontroller]

The growth path of single-chip microcomputer (avr basics) - 003 BOOT area of AVR single-chip microcomputer

The origin of the BOOT area is based on a simple principle, that is, the program of the microcontroller is stored in the FLASH, and to run the program, the FLASH memory must be accessed continuously. For general FLASH memory, it takes a certain amount of time to write data. Before the data is written, all the data in

[Microcontroller]

Implementing Complex Discrete Logic Using Microcontrollers

Developers can use the Configurable Logic Block (CLB) peripheral in the PIC16F13145 family of microcontrollers to implement complex discrete logic functions in hardware, thereby reducing the bill of materials (BOM) and developing custom application-specific logic. In many embedded system application

[Microcontroller]

Popular Resources
Popular amplifiers