L9662 datasheet(58/80 Pages) STMICROELECTRONICS

58 / 80 page

Functional description

L9662

58/80

DocID028325 Rev 1

High voltage mode

The High Voltage Mode is based on the SYNC Mode and will be used to communicate with

the external satellites via voltage modulation. When in this mode the valid sync time

selections would be tSYNC_high3 and tSYNC_high4.

During the High Voltage Mode it is necessary to disable the receiver of the sensor interface

until a complete data frame is sent. After sending a data frame the receiver must be enabled

again to receive the expected answer from the satellites. The microcontroller will control the

enabling and disabling of the receiver along with Sync pulse high time (tSYNC_highx) the

over SPI2 for each bit of the data frame.

Figure 13. High voltage mode communication

Satellite message decoding

The device is configurable for decoding of satellite messages based on either Manchester-1

or Manchester-2 decoding. Each of the four satellite channels has a Manchester decoder

that can be enabled or disabled through the CCR register.

For Manchester-1 decoding a logic 0 is defined as a signal transition from 1 to 0 at 50%

Duty cycle, logic 1 is defined as a signal transition from 0 to 1 at 50% Duty cycle. For

Manchester-2 decoding a logic 0 is defined as a signal transition from 0 to 1 at 50% Duty

cycle, logic 1 is defined as a signal transition from 1 to 0 at 50% Duty cycle. An example of

Manchester-1 and Manchester-2 decoding is given below.

Figure 14. Manchester-1/2 decoding diagram

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