Bus Master Functions

2006 BMW M CoupeSECTION Bus Master Functions

The SIM has two tasks to perform as Bus Master for the byteflight.

  • Generation of the synchronization pulses (Sync. Pulse)
  • Setting the satellites in alarm mode (Alarm Pulse)

In the ASE, the SIM is configured as byteflight  master (bus master). In principle, any satellite can be configured by software as bus master. However, there may only be one bus master in the system.

All other satellites (bus slaves) use the sync pulse for internal synchronization. Each slave can transmit telegrams between the sync. pulses on the byteflight  .

The SIM provides the synchronization pulses at intervals of 250 mues. The alarm mode is transmitted across the width of the sync. pulse. The duration of a sync. pulse in alarm status is approx. 2 mues. Normally, the synchronization pulse lasts approx. 3 mues.

The duration of a complete telegram can vary between 4.6 to 16 mues.

On the basis of all the available information provided by the sensors, the bus master (SIM) must decide whether the satellites are to be set in the alarm mode.

When the alarm mode is set by the SIM, all the trigger circuits (B+) of the ASE are placed on trigger standby.

Fig 1: Identifying Generation Of Synchronization Pulses (Sync. Pulse)
G03397751Courtesy of BMW OF NORTH AMERICA, INC.
RENDER: 1.0x

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