Introduce the Causes of Jitter in Use of Light-touch Key Switch
Release time：2018-12-01 Clicks： Click
We should pay attention to some problems when we touch the button switch lightly. Next we will introduce this problem in detail.
Among the many classifications of switches, touching the key switch and the mechanical key is also a characteristic of many products. Do you know the difference between the two?
1. The cost of tapping the key switch must be high, and the service life is not absolute.
2. The mechanical key is a light touch switch which is usually controlled by a computer board in the semi-automation period.
In theory, the scanning frequency of dynamic display of light touch button switch can not be less than 25Hz, and in practice, it usually needs more than 30Hz to have a better display effect. It's normal to display when you don't press the button. The display jitters when you press the button because the scanning frequency can meet the display requirement when you don't press the button. After pressing, the scanning frequency can't meet the requirement because of the increase of program and a lot of delay, so the phenomenon of "jitter" appears.
The key to solve the problem is how to reduce the running time of the key program to ensure that the scanning program can scan on time.
It is suggested that the program of the scanning display part should be placed in the interrupt processing part of the timer, so as to ensure the scanning frequency. In addition, the delay in the program of touching the key processing part of the key switch should be changed to the timing interrupt.