No ACK with i2c Write slave adress to TCA9555

Question

Running a test on a PIC16F18877 I encounter a problem with i2cWrite.

During sending an adress to a TCA9555 i can not get a proper ACK. After I2c start the function is called with slave adress 0x40. In fact 0x20 first 7 bits for slave adress complemented with 0 for Write on bit 0. A0;A1 and A2 are all pulled to GND. Testing with a different TCA9555 gives the same error.

I need to see ACK becomes 0 but the return value is 1.

The i2cWritefunction has been used in many projects and tested just now with a DS3231. From this device I get a proper ACK.

Stepping through the function shows the proper SDA high and low signals. Even visible on the SDA line itself.

I might be doing something wrong with the TCA9555 but have no idea what.

   bit i2cWrite(const unsigned char Byte)
       {
            unsigned char i = 0;
        for(i=0;i<8;i++)        // Repeat for every bit
        {
          Set_SCL_Low;
          Delay();
          // when it is confirm that SCL is low
          if((Byte<<i)&0x80)    // Place data bit value on SDA pin
            Set_SDA_High;   // If bit is high, make SDA high
          else          // Data is transferred MSB first
            Set_SDA_Low;    // If bit is low, make SDA low
          Delay();
          Set_SCL_High;     // So that slave can ackknowldege
          Delay();
          Delay();
         }
         // Get ACK from slave
         Set_SCL_Low;
         Set_SDA_High;
         Delay();
         Delay();
         Set_SCL_High;
         Delay();
         Delay();
         return SDA;
        }