LSM303DLMTR datasheet(20/38 Pages) STMICROELECTRONICS

20 / 38 page

Digital interfaces

LSM303DLM

20/38

Doc ID 018725 Rev 1

Magnetic signal interface reading/writing

The interface uses an address pointer to indicate which register location is to be read from

or written to. These pointer locations are sent from the master to this slave device and

succeed the 7-bit address plus 1 bit read/write identifier.

To minimize communication between the master and magnetic digital interface of

LSM303DLM, the address pointer updates automatically without master intervention.

This automatic address pointer update has two additional features. First, when address 12

or higher is accessed, the pointer updates to address 00, and secondly, when address 08 is

reached, the pointer rolls back to address 03. Logically, the address pointer operation

functions as shown below.

If (address pointer = 08) then the address pointer = 03

Or else, if (address pointer >= 12) then the address pointer = 0

Or else, (address pointer) = (address pointer) + 1

The address pointer value itself cannot be read via the I2C bus.

Any attempt to read an invalid address location returns 0, and any write to an invalid

address location, or an undefined bit within a valid address location, is ignored by this

device.

LSM303DLMTR Datasheet(PDF) 20 Page - STMicroelectronics