Theory of operation

AN2855

4/8

1.2

Entering single click recognition mode

To enable the single-click recognition function, the device must first be configured for power-

down mode driving PD pin to GND. Then the following sequence of commands must be sent

I2C_Read(0x5D, 0x16, Value_1);

I2C_Write(0x5D, 0x16, Value_1 & 0x1F);

I2C_Write(0x1D, 0x3Bh, 0x77h);

I2C_Write(0x1D, 0x3Ch, 0x07h);

I2C_Write(0x1D, 0x3Dh, 0xFEh);

I2C_Write(0x1D, 0x3Eh, 0x10h);

I2C_Write(0x1D, 0x3Fh, 0xFFh);

I2C_Write(0x1D, 0x38h, 0x15h);

I2C_Write(0x1D, 0x20h, 0x47h);

I2C_Write(0x1D, 0x22h, 0x07h);

where I2C_Read and I2C_Write have the following syntax:

I2C_Read(SlaveAddress, SubAddress, DestinationValue);

I2C_Write(SlaveAddress, SubAddress, SourceValue);

At the end of the sequence the device will be in a power on state, ready to operate in single-

click recognition mode and orientation detection is no longer active.

1.3

Entering double-click recognition mode

As with single-click recognition, to enable the double-click recognition function the device

must be first configured for power-down mode driving PD pin to GND. Then the following

I2C_Read(0x5D, 0x16, Value_1);

I2C_Write(0x5D, 0x16, Value_1 & 0x1F);

I2C_Write(0x1D, 0x3Bh, 0x77h);

I2C_Write(0x1D, 0x3Ch, 0x07h);

I2C_Write(0x1D, 0x3Dh, 0xFEh);

I2C_Write(0x1D, 0x3Eh, 0x10h);

I2C_Write(0x1D, 0x3Fh, 0xFFh);

I2C_Write(0x1D, 0x38h, 0x2Ah);

I2C_Write(0x1D, 0x20h, 0x47h);

I2C_Write(0x1D, 0x22h, 0x07h);