Detection circuit capable of detecting a plurality of arbitrary-combination keys by low cost, and processing method

[0046] Such as Figure 1-6 As shown, according to the embodiment of the present invention, the detection circuit and processing method that can detect a plurality of arbitrary combination keys include single-chip microcomputer, MCU, CPLD, FPGA, ARM, control chip, matrix key circuit, wherein, the control chip is provided with R +C IO pins, of which the R line controls the IO as an input, and has an external interrupt function, which can trigger a single-edge rising, a single-edge falling edge, or a double-edge trigger. The IO pin is internally equipped with floating floating , Open-drain, push-pull, pull-up, pull-down and other IO function settings, the vertical C line controls the IO to switch between output and input;

[0047] The matrix button circuit includes R horizontal branches and C vertical branches, a key position is formed at the intersection of the horizontal branches and the longitudinal branches, and the horizontal R line branch and the longitudinal C line branch 0

[0050] Such as Figure 1-6 As shown, the R line of the controller IC has an AD sampling function, and the AD function is set as an input with a wake-up function during sleep. When the R line is externally connected to the GND with a pull-down resistor, the R line controls The level read by the IO defaults to low level. At this time, only one C line outputs high level during button scanning, and the other C lines output low level. When the button is pressed and the connection is turned on, the corresponding R line will pull Higher than a certain level, read the voltage signal of the resistor divider through AD. When it is greater than the set threshold, it is considered that the button is pressed and turned on. When the AD level is read below the threshold of a ground, it is considered that the button is sent On, when all the buttons on the C line are pressed, the voltage read by the R line will be greater than a certain value. In addition, the level signals of the R line will not

[0052] Such as Figure 1-6 As shown, when the controller IC has no AD function, the voltage comparison circuit can be used to compare the voltage, and the output signal is read to the R line. At this time, the R line can be used as an input with pull-up or floating or pull-down according to the application circuit. state, when the resistance of the key part is connected to GND, the level read by the corresponding R line control IO is low level by default. At this time, only one line of C outputs high level during key scanning. When it is on, the corresponding R line will pull up a certain level. When it is greater than the divided voltage level set by the comparator, the output level of the comparator will be reversed, and the control chip R line can recognize that the state of the level is high. or low level, it is considered that a button is pressed; similarly, when the resistance of the button part is connected to VDD, the level read by the corresponding R line to control the