Interface circuit between 8253 and 8031

Pulse width measurement refers to measuring the duration from a certain state ("l" or "O") of the switching input. Pulse width
measurement can be achieved by using a universal interface counter chip . 8253 is a typical 8-bit data bus timer interface chip. Figure 27-26 is a pulse width measurement interface circuit composed of 8253 and 8031 . The working mode of 8253 is defined by working mode control . The control word definition is shown in Figure 27-27. It has 6 working modes i' which can complete counting, pulse width measurement and other tasks. Pulse width measurement can be implemented using mode O or mode 2. When using mode o, the microcontroller needs to query the pulse status. When using mode 2, the interrupt signal can be generated by the GA TE signal, which requires the measured pulse state to be high level, the traced signal is connected to GA TE , and CLK is connected to the reference pulse.