I2C slave address 7 bit vs 10 bit

[Guest]

Hi,

I have a master I2C talking to a salve.

I'm having problems with the salve address.

My slave is set to 0x12 as follows:
#use I2C(slave, sda=PIN_B4, scl=PIN_B6, address=0x12, FORCE_HW)
It however only communicates with the master when the master sets the address to 0x1E.

Do I have a problem with 7 bit vs 10 bit addressing modes?

Thanks for your time

Jeff

[Guest]

I fixed the problem by relocating

#use I2C(slave, sda=PIN_B4, scl=PIN_B6, address=0x12, FORCE_HW)

This brings me to my next question. I have a backplane that can hold 7 slaves. The salves address is determined by the solt postion of the backplane. I have a subroutine that reads the slot position and then sets the slave address. This routine was causing my first problem EVEN THOUGH I NEVER CALLED the routine!

Is this a compiler problem?

switch (slotID)
{
case 0:
#use I2C(slave, sda=PIN_B4, scl=PIN_B6, address=0x10, FORCE_HW)
break;
case 1:
#use I2C(slave, sda=PIN_B4, scl=PIN_B6, address=0x12, FORCE_HW)
break;
case 2:
#use I2C(slave, sda=PIN_B4, scl=PIN_B6, address=0x14, FORCE_HW) break;
case 3:
#use I2C(slave, sda=PIN_B4, scl=PIN_B6, address=0x16, FORCE_HW)
break;
case 4:
#use I2C(slave, sda=PIN_B4, scl=PIN_B6, address=0x18, FORCE_HW)
break;
case 5:
#use I2C(slave, sda=PIN_B4, scl=PIN_B6, address=0x1a, FORCE_HW)
break;
case 6:
#use I2C(slave, sda=PIN_B4, scl=PIN_B6, address=0x1c, FORCE_HW)
break;
case 7:
#use I2C(slave, sda=PIN_B4, scl=PIN_B6, address=0x1e, FORCE_HW)
break;
}
}

[Guest]

You can´t do that. #use is a pre-processor directive, so the last one found in the source code will be the one that works. Try to change the slave address wrtiting directly to the respective register.

[Guest]

Thanks!

I'll give it a shot.

[Guest]

Code is now working


#BYTE SSPADD = 0x93


SSPADD = i2cSlotAddress[slotID]; // load slave address