MCP23017 Io Expander problem

Mbed OS Bugs
1

Hi,
I have project with using LPC1768 the control the multiple IoExpander.
I use 3 IoExpanders in my project .
In these conditions while ı was controlling the IoExpander my expander sometimes Even though I pull the line to 1, it pulls to 0 line.It is problem for my project.

I have shared the io expander part of the code I run my project below, if necessary, I can share the rest.
I’m using the i2c protocol for communicate the IoExpander.

void IoExpander()
{
    Expander1 = new MCP23017( p9, p10, 0x42);  //Initiliaze MCP23017
    Expander2 = new MCP23017( p9, p10, 0x40);
    Expander3 = new MCP23017( p9, p10, 0x44);
    Expander1->config(0,0,0);
    Expander2->config(0,0,0);
    Expander3->config(0,0,0);
    Expander1->write_bit(0,15);
    Expander1->write_bit(1,6);                 //System Power Led
    //Fault Reset and Remotes
    if(Fault_Reset == true) {
        Expander2->write_bit(0,7);
    } else {
        Expander2->write_bit(1,7);
    }
    if (G == true) {
        Expander2->write_bit(0,6);
    } else {
        Expander2->write_bit(1,6);
    }
    if(F == true) {
        Expander2->write_bit(0,5);
    } else {
        Expander2->write_bit(1,5);
    }
    if (C == true) {
        Expander2->write_bit(0,4);
    } else {
        Expander2->write_bit(1,4);
    }
    Fault_AD1 = Expander2->read_bit(8);
    Fault_AD2 = Expander2->read_bit(9);
    Fault_AD3 = Expander2->read_bit(10);
    Fault_AD4 = Expander2->read_bit(11);
    Fault_AD5 = Expander2->read_bit(12);
    Fault_AD6 = Expander2->read_bit(13);

    Expander2->write_bit(0,0);   // Rsv Faults Sets Low        
    Expander2->write_bit(0,1);   // RSV_FLT5
    Expander2->write_bit(0,2);   //RSV_FLT4
    Expander2->write_bit(0,3);   //RSV_FLT3
    //Exp1 Reserve
    Expander1->write_bit(0,0);   //Warning Led
    Expander1->write_bit(0,2);   //Caution
    Expander1->write_bit(0,4);   //SysDOWN
    Expander1->write_bit(0,12);
    Expander1->write_bit(0,13);
    Expander1->write_bit(0,14);
    //Exp3 Reserve
    for (y = 0; y < 16; y++) {
        Expander3->write_bit(1,y);
    }
//For String Manipulation
    if (Fault_AD1 == true ) {                       // 
        FAD1="T";
    } else {
        FAD1="F";
    }
    Fault_AD2 = Expander2->read_bit(9);
    if (Fault_AD2 == true ) {
        FAD2="T";
    } else {
        FAD2="F";
    }
    Fault_AD3 = Expander2->read_bit(10);
    if (Fault_AD3 == true ) {
        FAD3="T";

    } else {
        FAD3="F";
    }
    Fault_AD4 = Expander2->read_bit(11);
    if (Fault_AD4 == true ) {
        FAD4="T";
    } else {
        FAD4="F";

    }
    Fault_AD5 = Expander2->read_bit(12);
    if (Fault_AD5 == true ) {
        FAD5="T";
    } else {
        FAD5="F";
    }
    Fault_AD6 = Expander2->read_bit(13);
    if (Fault_AD6 == true ) {
        FAD6="T";
    } else {
        FAD6="F";
    }
    if( Connection_Info == true) {
        Expander1->write_bit(1,5);
    } else {
    }
    if ( Fault_AD1 == false || Fault_AD2 == false || Fault_AD3 == false || Fault_AD4 == false || Fault_AD5 == false || Fault_AD6 == false) {         //Fault Detection
        Expander1->write_bit(1,1);
        MasterFault="F";
         } else {
        Expander1->write_bit(0,1);
        MasterFault="T";
        } 
        if ( C == true || G == true || F == true ) {         //Manual Detection
        Expander1->write_bit(1,3);
         } else {
        Expander1->write_bit(0,3);    
        }
          
    delete Expander1; // Pointers causes memory leak we use for that
    delete Expander2;
    delete Expander3;
}
int main()
{
  while(true) {
        Led1 = !Led1;
        IoExpander();
    }

I’m using delete function for

I’m using for the library ;MCP23017 - Reset causes problems solved | Mbed
In this library I disabled the reset function in initialize for the resetting causes problems.
How can I block the MCP23017 pull to 0 zero when ı was set the 1 .

2

Hello Taha,

Try to move the lines below

    Expander1 = new MCP23017( p9, p10, 0x42);  //Initiliaze MCP23017
    Expander2 = new MCP23017( p9, p10, 0x40);
    Expander3 = new MCP23017( p9, p10, 0x44);

from the IoExpander function to the main function:

int main()
{
    Expander1 = new MCP23017( p9, p10, 0x42);  //Initiliaze MCP23017
    Expander2 = new MCP23017( p9, p10, 0x40);
    Expander3 = new MCP23017( p9, p10, 0x44);

    while(true) {
        Led1 = !Led1;
        IoExpander();
    }
}

and delete the lines below from the IoExpander function:

    delete Expander1; // Pointers causes memory leak we use for that
    delete Expander2;
    delete Expander3;