ADS1115 on RP2040 Wire, 0x4B is busy

[robtillaart]

ADS1115 on RP2040 Wire, 0x4B is busy

[RobTillaart]

Thanks for filing the issue,

I have no RP2040 so I cannot confirm the issue so I need to think how to tackle this one.

(I see a a lot of bad news from France - fires, canicule(?) - also in your neighbourhood?)

[RobTillaart]

Do you have an I2C scanner application?
Please disconnect all external devices, do a scan to see if there are "hidden" devices on the board.

if no 0x4B device, connect the ADS1115 as 0x4B and try again.

---

e.g. https://github.com/RobTillaart/MultiSpeedI2CScanner

[RobTillaart]

Given that the ADS was working with the MEGA (5V) indicates that the ADS itself is OK.

another thought...
Are you using pull up resistors on the SCL / SDA lines?
if so which value?
As the RP2040 is a 3V3 device, there might be an electric difference, so you might try without pull ups.
(to get address 0x4B the ADDR pin needs to connect to SCL, that's why I ask)

[RobTillaart]

Found this issue - arduino/ArduinoCore-mbed#448 -
It might or might not be related, at least it is also the SCL line that fails.

Have you tried switching the devices on Wire0 and Wire1 bus?

[f5exo]

Thank's for your reply Rob.
I am in the west of France, and I confirm it is very hot.
Yes the ADS is supplied with 3.3V
On arduino it was supplied with 5V
I use the same probes addressable by stap.
which are functional on arduino.

Here is simple test file:
only the 3 addresses are seen, alone or together.
I am looking for an i2c scanner in C not in python.

//-- ADS1115 16 bits --
//https://github.com/RobTillaart/ADS1X15
#include "ADS1X15.h"
// ADS1115 address
ADS1115 ADC_A(0x48);
ADS1115 ADC_B(0x49);
ADS1115 ADC_C(0x4A);
ADS1115 ADC_D(0x4B);

// -- module RTC --
#include "RTClib.h"
#define TIME_24_HOUR true
RTC_DS3231 rtc;

// -- Librairies TFT 3.5  --
#include "TFT_eSPI.h"
TFT_eSPI tft = TFT_eSPI();


bool sonde_A = false;
bool sonde_B = false;
bool sonde_C = false;
bool sonde_D = false;

// Gain value
int G_A = 2;
int G_B = 2;
int G_C = 2;
int G_D = 2;



//----------------SETUP--------------------------------------
void setup() {

  // vitesse d'envoi  pour l'USB
  Serial.begin(57600);  // debug
  //inputString.reserve(200);
  Serial1.begin(57600);
  //-------------------------------------------------------------
  // -----------Module horloge temps reel -----------------------
  //-------------------------------------------------------------
  // mise a jour horloge RTC
  // **** verifier sir on est bien en wire1 ****
  if (!rtc.begin(&Wire1)) {
    Serial.println(F("Couldn't find RTC"));
    Serial.flush();
    abort();
  }
 
  // initialisation Ecran
  tft.init();
  tft.setRotation(3);
  //tft.fillScreen(0x0000);
  tft.fillScreen(TFT_BLACK);

  // -- probe presence test --
  test_Probe();
  ADS1115_Init();
}



//-----------------------------------------------------------
//     ** Probe presence test **
//-----------------------------------------------------------
void test_Probe()
{  
  tft.fillScreen(0x0000);

  // Test if the probes respond

  if (ADC_A.begin()) sonde_A = true;
  if (ADC_A.isConnected())tft.println(F("Sonde A is connected"));
  if (ADC_A.isBusy())tft.println(F("Sonde A is Busy"));
  delayMicroseconds(200);

  if (ADC_B.begin()) sonde_B = true;
  if (ADC_B.isConnected())tft.println(F("Sonde B is connected"));
  if (ADC_B.isBusy()) tft.println(F("Sonde B is Busy"));
  delayMicroseconds(200);

  if (ADC_C.begin()) sonde_C = true;
  if (ADC_C.isConnected()) tft.println(F("Sonde C is connected"));
  if (ADC_C.isBusy()) tft.println(F("Sonde C is Busy"));
  delayMicroseconds(200);

  if (ADC_D.begin()) sonde_D = true;
  if (ADC_D.isConnected()) tft.println(F("Sonde D is connected"));
  if (ADC_D.isBusy()) tft.println(F("Sonde D is Busy"));
  delayMicroseconds(200);

  delay(9900);
}


void ADS1115_Init()
{
  // --  initialisation ADS1115 --
  if (sonde_A == true) {
    ADC_A.begin();
    ADC_A.setGain(G_A);    
    ADC_A.setMode(1); 
    ADC_A.setDataRate(6);  
    ADC_A.readADC(0);
  }
  //delay(40);
  if (sonde_B == true) {
    ADC_B.begin();
    ADC_B.setGain(G_B);
    ADC_B.setMode(1);
    ADC_B.setDataRate(5);
    ADC_B.readADC(0);
  }
  //delay(40);
  if (sonde_C == true) {
    ADC_C.begin();
    ADC_C.setGain(G_C);
    ADC_C.setMode(1);
    ADC_C.setDataRate(6);
    ADC_C.readADC(0);
  }
  //delay(40);
  if (sonde_D == true) {
    ADC_D.begin();
    ADC_D.setGain(G_D);
    ADC_D.setMode(1);
    ADC_D.setDataRate(5);
    ADC_D.readADC(0);
  }
  //delay(40);
  /*
   val 0 Gain de 2/3 (par défaut)  +/- 6.144V  0.1875mV
   1 Gain de 1 +/- 4.096V    0.125mV
   2 Gain de 2 +/- 2.048V    0.0625mV
   4 Gain de 4 +/- 1.024V    0.03125mV
   8 Gain de 8 +/- 0.512V    0.015625mV
   16 Gain de 16  +/- 0.256V  0.0078125mV
  */
}

void loop() {
}

(added code tags for syntax highlighting)

[RobTillaart]

I am looking for an i2c scanner in C not in python.

maybe this one - https://github.com/RobTillaart/MultiSpeedI2CScanner

[RobTillaart]

Your code shows no things that look wrong (as 3 out of 4 work it should be OK)

What is the address of the RTC?

How is the TFT controlled?
SPI I assume?

[f5exo]

Are you using pull up resistors on the SCL / SDA lines?
if so which value?
I just looked on the module used (aliexpress) and yes there is a pull up at 10k for these two.

i don't use the 3.3v of Rapsberry , i use 5v with 3.3 external regulator.

As the RP2040 is a 3V3 device, there might be an electric difference, so you might try without pull ups.
(to get address 0x4B the ADDR pin needs to connect to SCL, that's why I ask)

Yes i have a PCB with addressable pins, and i can choose one of four adress.
So I can connect the 4 probes on the same bus with the correct addresses.

TFT is on SPI0

[f5exo]

Last news
I confirm that with the simplest assembly: RP2040 and ADS1115 only: the result is identical .

Serial result.

TEST ADS1115
Sonde A is connected
Sonde A is OK
Sonde B is Busy
Sonde C is Busy
Sonde D is Busy
TEST ADS1115
Sonde A is Busy
Sonde B is Busy
Sonde C is Busy
Sonde D is Busy

[f5exo]

Hello Rob
Good news
Finally, I added a pull up of 4.7K on the I2C Bus
and now I see each address alone, or all 4 together.

Thank you very much for your help, it helped me a lot.
The best for you.

With the scan I was able to see the address of the RTC: 0X68

[RobTillaart]

mmm, no clue yet
Have you tried a smaller pull up resistor e.g. 4K7 or 2K2 or even 1K?
Do you have a scope to see the signals over the I2C bus?

---

oops crosspost :)

[RobTillaart]

Good to hear it is solved, you may close the issue .

[f5exo]

I hear emails before I receive them....hi
Thanks you for all.
Erick at Laval West of France.

[RobTillaart]

You're welcome