Slave Address seemingly different from data sheet

Sorry if this isn't the right board to ask a question like this. I recently picked up a MikroElektronika "IR Sense Click" which comes with an AK9750 IR sensor mounted on it. I've been struggling for several days to get this thing to read. I finally ended up moving the jumps on the front such that the CAD0 pin was high and CAD1 pin was Low. According to the data sheet this should give the device a Slave Address of 65H. (101) However, it will communicate now, but only under slave address 66H. Does any one know why the slave address is different from the data sheet?

https://www.mikroe.com/ir-sense-click

The datasheet may be specifying the I2C address as an 8 bit value. The Wire library uses a 7 bit addresses (addr << 1 )

Run a I2C bus scan program that reports the 8 bit and 7 bit address of any device it finds.

I finally ended up moving the jumps on the front such that the CAD0 pin was high and CAD1 pin was Low. According to the data sheet this should give the device a Slave Address of 65H. (101)

That either means that you soldered the resistor the wrong way around or that the label on the board is wrong. Did you check if the connection of the middle solder point is connected to the correct pin of the chip?

Figure-1: I2C Bus Address and R-W/ Bit

|500x95 Figure-2: Permissible slave addresses

1. In Arduino Platform, the I2C Bus address is always 7-bit (Fig-1). R-W/ (Data Direction Bit) bit is added at the end of the I2C Bus address to form an 8-bit value what is known as Control Byte (Fig-1).

2. When the Master executes Wire.write() command, 0 is added at the end of the I2C Bus address. 1 is added at the end of the I2C Bus address when the Master executes the Wire.requestFrom() command.

3. Figure-2 clearly indicates that the CAD0/CAD1 determine the lower 2 address bits (A0/A1) of the sensor and the permissible addresses are: 0b1100100 (0x64), 0b1100101 (0x65), and 0b1100110 (0x66).

As Post#2 has advised you, check your wiring/soldering.

pylon: That either means that you soldered the resistor the wrong way around ....

When did resistors become polarized?

When did resistors become polarized?

They are not polarized (actually they're 0Ω, so replacements for solder bridges) but you can have them on two places soldered.