HC SR04 using internal registers

Projects Programming
1

Hi! Someone can explain me how to use the sensor HC SR04 using the internal register of Arduino? (using PORTx, DDRx ecc...) Thanks!

2

you will need a timer to play with your module.

PORTX and other register command allow you to set or clear Pin on GPIO. I propose you to read the manuel user where every one are detailled.
Then, you could be able to set a specific pin with a command like:

PORTA |= 0b00000001

assuming the pin to set is the first in the corresponding register. It is a (fancy) quick method to play on pin but to put the right TRIGGER SIGNAL (10ms) and listen for the ECHO (between 5 and 30ms), you will need a timer involved, and maybe an interrupt to detect the ECHO.
You can see the Register command as a substitute for digitalWrite() but it won't make the job alone.

3

Thanks, but actually I have no idea how to start writing the code. I have been using Arduino for a short time, I am able to use the sensor normally, but not using the registers.

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6

If you already have it working, why do you need to change to a low-level register technique?

7

that will not the perfect example I want for you, but here is a (french written) article explaining how to set timer (the missing part for your module!) with Register commands

https://www.locoduino.org/spip.php?article88

see this example:

void setup () {
  pinMode (Led, OUTPUT);
  pinMode (Led2, OUTPUT);
  cli(); // Désactive l'interruption globale
  bitClear (TCCR2A, WGM20); // WGM20 = 0
  bitClear (TCCR2A, WGM21); // WGM21 = 0 
  TCCR2B = 0b00000110; // Clock / 256 soit 16 micro-s et WGM22 = 0
  TIMSK2 = 0b00000001; // Interruption locale autorisée par TOIE2
  sei(); // Active l'interruption globale
}

TCCR2B and TIMSK2 are two register's adresses. By directly change its value (like TIMSK2 = 0b00000001), you change the settings of the function.
To be able to use this, the register mapping is mandatory (user manual of the chip). For the rest, it is a very classical "attribute a value to a memory".
In the example and my fisrt answer, I talk about WRITING on a register, but the opposite is true, and you can read the register value (for example a Led state plugged in GPIO).

8

Thanks, I will try in this way

9

Because I'm a university student and I need to use registers for an exam.

10

And study nowadays is asking in a forum for help?

11

always better than payed enginner asking for an ever written code.

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