Asking questions for I2C channel communication

Projects Programming
1

I tried to make a code as below:
I have four I2C channels. The timing gap of starting time (or activation time) between each channel will be 40ms. Also, the activation time of each channel will be 140ms. Here is the figure to run.

image
image1346×845 27.1 KB

Also here is the code what I used.

  #include <Wire.h>
  #include <SparkFun_I2C_Mux_Arduino_Library.h>
  #include <Adafruit_DRV2605.h>

  #define QWIIC_MUX_DEFAULT_ADDRESS 0x70
  QWIICMUX myMux;
  Adafruit_DRV2605 drv[8];
  unsigned long channelStartTime;
  unsigned long channelInterval = 30;
  unsigned long channelDuration = 140;
  unsigned long startTimes[4] ={0};
  bool i_Going_Up = false;
  bool j_Going_Up = false;
  bool k_Going_Up = false;
  bool l_Going_Up = false;
  int flag=0;
  int loopCount =0 ;
  boolean channelInProgress = false;
  char receivedChar;  
  unsigned long currentTime1 = 0;
  unsigned long previousTime[4] = {0};
  int currentChannel = 0;

  byte i = 0;
  byte j = 0; 
void setup() {
    Serial.begin(115200);
    Serial.println("Qwiic Mux Shield Read Example");
    Wire.begin();

    if (myMux.begin() == false)
    {
      Serial.println("Mux not detected. Freezing...");
      while (1)
        ;
    }
    Serial.println("Mux detected");
    byte currentPortNumber = myMux.getPort();
    Serial.print("CurrentPort: ");
    Serial.println(currentPortNumber);  
    for (int i=0;i<8;i++){
      performI2CChannelOperation(i);
    }
    channelStartTime = millis();  // Initialize the start time

  }
  void Single_I2C(){
    if (i_Going_Up){
      singleActuator(0);
      drv[0].setRealtimeValue(127);
      delay(100);
      drv[0].setRealtimeValue(0);
      disablesingle(0); 
    }
    if (j_Going_Up){
      singleActuator(1);
      drv[1].setRealtimeValue(127);
      delay(100);
      drv[1].setRealtimeValue(0);
      disablesingle(1);  
    }
    if (k_Going_Up){
      singleActuator(2);
      drv[2].setRealtimeValue(127);
      delay(100);
      
      drv[2].setRealtimeValue(0);
      disablesingle(2);  
    }
    if (l_Going_Up){
      singleActuator(3);
      drv[3].setRealtimeValue(127);
      delay(100);
      drv[3].setRealtimeValue(0);
      disablesingle(3);  


    }

  }


  void performI2CChannelOperation(uint8_t i){
    singleActuator(i);
    Wire.beginTransmission(QWIIC_MUX_DEFAULT_ADDRESS);
    Wire.write(1<<i);
    Wire.endTransmission();
    drv[i].begin();
    drv[i].setMode(DRV2605_MODE_REALTIME);
    drv[i].writeRegister8(DRV2605_REG_OVERDRIVE,0xFF);
    drv[i].writeRegister8(DRV2605_REG_FEEDBACK, 0x86);
    drv[i].useLRA();
    drv[i].selectLibrary(6);
    delay(100);
  }

  void singleActuator(uint8_t i){
    startTimes[i]= millis();
    Wire.beginTransmission(QWIIC_MUX_DEFAULT_ADDRESS);
    Wire.write(1<<i);
    Wire.endTransmission();
  }
  
  void disablesingle(uint8_t i){
    Wire.beginTransmission(QWIIC_MUX_DEFAULT_ADDRESS);
    Wire.write(0<<i);
    Wire.endTransmission();
  }
 void loop() {unsigned long currentTime = millis();

  if (currentTime - channelStartTime >= channelInterval) {
    if (channelInProgress) {
      // Deactivate the current channel
      drv[currentChannel].setRealtimeValue(0);
      disablesingle(currentChannel);
      channelInProgress = false;
    } else {
      // Move to the next channel and activate it
      currentChannel = (currentChannel + 1) % 4;
      singleActuator(currentChannel);
      drv[currentChannel].setRealtimeValue(127);
      channelInProgress = true;
      channelStartTime = currentTime;
    }
  }

  if (channelInProgress && (currentTime - channelStartTime >= channelDuration)) {
    // Deactivate the current channel after the specified duration
    drv[currentChannel].setRealtimeValue(0);
    disablesingle(currentChannel);
    channelInProgress = false;
  }
}

Please fix it ...

2

What is your question?

3

My question is first whether it is the right code as what I described before the code. Second one if it is not, please let me know how to make a code.

4

What are these devices? Perhaps describing your project woukd help me make any sense of your timing diagram.

Yes, maybe it could be reverse engineered from your code, sorry, too old to spend time on that!

Maybe you should focus on separate issues.

  1. get four things to happen on your time schedule

That could be printing or illuminating separate LEDs. You could vastly slow down the time scale until you had reliable mechanism for doing things on time in order.

  1. come to grips with how the I2C multiplexer works

To be sure you are able to talk with a particular device from all them, perhaps determined by an index variable, just an int 0 or 1 or whatever to say which.

  1. 1 + 2 = 3. Fix the timing back to rapid, throw in your ability to talk to the device you want at will and…

you'll be done.

It will be easier to help you with each of the two totally separate aspects of the entire goal.

a7

5

I am confused. When you ran the code, did it do what you wanted it to do? If so, it's likely the right code. If it didn't do what you wanted, then how did it fail?

6

I think that you want to solve something that does not exist.
When we get a question like this, then it is often a XY problem: https://xyproblem.info/
What do you want to achieve with that timeout on the I2C bus ?

The DRV2605L haptic controller has only one I2C address, so you need indeed a multiplexer.
The TCA9548A chip is a good I2C multiplexer.

If you want to control one of the haptic controllers, then you set the mux and send commands to that controller. How long the mux is activated does not matter.

If you want to disable all the I2C channels when not using the I2C bus, then you can do that directly after using one of the controllers.

The I2C bus is blocking, when a function of the Mux library returns, then the I2C session has completely finished and there is not need to keep the I2C active for something.

7

If you can provide illuminating separate LEDs with a specific duration time (Here 140ms) and time gap (Here 40ms) between the starting (on-time) of each LED, would you like to provide it? 140ms later after it illuminates, it will turn off also.

8

Can you tell us what your project is ?

Do you want to control both the haptic controllers and leds ? That is no problem, but please do not try to make the I2C bus active or not, just use the I2C bus when needed.

9

I am a little bit confused about whether it is the right code as I described.
If I change the channelInterval variable small enough or as 0 , it should be perceived as simultaneous activation. But it still has some time gap between each channel.

10

Did you write this yourself? If not, where did you get it? If it's some sort of example from a supplier, surely it would describe there what it does.

11

Beginning to smell ChatGPT here... Is that so, @kylerhong

12

Hopefully, I want to control four haptic controllers. I also have I2C multiplexer which I have used and written in my code.
My project is that I want to activate four vibration motors that are driven by the haptic driver. There should have specific time gap between each vibration activation starting time and each vibration will vibrate for specific duration time.

13

It is myself

14

Then write code that does that timing, and when you need to send something to a haptic controller, use a function that also sets the mux.

You can start with a very small test-sketch to blink 4 leds with the timing that you want (without I2C bus, just 4 leds).

1 Like
15

If you provide that you describes just using LED on/off please let me know it.

16

It is preferred to help you get something you've written to work.

But if I were to, I would need to see the diagram extended to show what happens and how the cyclic nature and staggered timing works out over a few cycles.

Or at least one and a half complete cycles.

What makes the cycles start and stop? Once initiated should we get one cycle that produces all four vibrations, or should the cycle repeat until it is told to stop?

If a repeating cyclic vibration pattern is being done, should stopping it just stop it no matter where in the pattern you are, or might you want to stop later, possibly, after the four part ps were all done?

If you don't answer these questions for us and yourself before you code anything, you will get the accidental answers that the code will provide for you when it runs…

a7

17

Once one vibration activates, it will stop 140ms later after it activates. Moreover, 40ms later after the first vibration activates, 2nd vibration will activate. Then, 1->2->3->4 will activate sequentially with a time gap of 40 ms. Then, if last vibration activates for 140ms, the sequential activation (from 1 to 4) will be stopped. Does it make sense?

18

Maybe. This seems ambiguous

Then, if last vibration activates for 140ms

Could you mean after the last vibration finishes, we done?

A diagram would be better. Thumbs up or down this diagram and say what makes it all start, or would make it go again.

Is anything else needed to happen whilst this sequence is playing out?

image
image2048×1679 263 KB

Sry the time line is not well scaled. If it looks like I drew that with my finger sitting under an umbrella at the beach with a half-empty cold one next to me, there's a reason for that.

a7

19

yes that should be what I want to do. Thanks.

20

This is a start (with delays):

// Timing of 4 things, starting 40ms after each other, staying active 140ms.
//
// Forum: https://forum.arduino.cc/t/asking-questions-for-i2c-channel-communication/1186203/16
// This Wokwi project: https://wokwi.com/projects/380693069509691393
//
// I can think of 4 good solutions.
// This is with delays.
// The code will do that sequence at the press of a button.

const int buttonPin = 2;

void setup() 
{
  pinMode(buttonPin, INPUT_PULLUP);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);
}

void loop() 
{
  int button = digitalRead(buttonPin);
  if(button == LOW)
  {
    digitalWrite(4, HIGH);
    delay(40);
    digitalWrite(5, HIGH);
    delay(40);
    digitalWrite(6, HIGH);
    delay(40);
    digitalWrite(7, HIGH);
    delay(20);
    digitalWrite(4, LOW);
    delay(40);
    digitalWrite(5, LOW);
    delay(40);
    digitalWrite(6, LOW);
    delay(40);
    digitalWrite(7, LOW);
  }
}

afbeelding
afbeelding771×318 3.9 KB

Try it in Wokwi: Sequence with delay - Wokwi ESP32, STM32, Arduino Simulator