Pi4j pin analog bus, several ideas of control transmission and data transmission

We know Java Language can delay in milliseconds , Such as :Thread.sleep(1), But when we need a serial port line for control transmission , When data is transmitted , Microsecond level delay is required , How can this be controlled ？

java The language itself api Corresponding functions are not provided . as a result of jvm The instruction set of cannot be controlled to the microsecond level ？

pi4j The bottom layer used is wiringPi, that wiringPi Can pass microTime Gets the current number of milliseconds , But by looking at api, Encapsulated... Not found microTime Methods , Therefore, the corresponding microsecond delay function cannot be found directly .

What should I do if I can't find it ？

1. Encapsulate the interface functions by yourself . But because of jvm The instruction execution of the virtual machine itself will take a certain clock cycle , At the clock speed of raspberry pie , Basically these jvm Level instructions will cause inaccurate delay in microseconds .

2. Encapsulate complete business functions into wiringPi, Bind deferred functions and business logic to non - java On the underlying code , Extend business functions to the underlying code . Use it like this Java Language encapsulates a closed-loop business scenario , To achieve microsecond level business layer control .

3. Use it directly c Language or low-level language , Write business logic , use Java Language call

 

in any case , such gpio Of i/o Pin as bus （ for example DHT11 Temperature and humidity sensor data reading ）, Can't be used directly Java To control microsecond delay . The only thing we can do is to bypass java Delay microsecond level function , Instead, it puts functionality on the underlying language , Form a business closed loop , Reuse java Encapsulate a complete business scenario , Provide overall business functions externally . This compromise can solve the problem of data reading . But it depends on the underlying language , for example c Language learning .