STLUX385ATR datasheet(13/126 Pages) STMICROELECTRONICS

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STLUX

System architecture

126

System architecture

The STLUX devices family generates and controls PWM signals by means of a state

machine, called SMED (state machine event driven). Figure 1 gives an overview of the

internal architecture.

Figure 1. STLUX internal design

The core of the device is the SMED unit: a hardware state machine driven by system

events. The SMED includes 4 states (S0, S1, S2 and S3) available during running

operations. A special HOLD state is provided as well. The SMED allows the user to

configure, for every state, which system events will trigger a transaction to a new state.

During a transaction from one state to the other, the PWM output signal level can be

updated.

Once a SMED is configured and running, it becomes an autonomous unit, so no interaction

is required since the SMED automatically reacts to system events.

Thanks to the SMED's 96 MHz operating frequency and their automatic dithering function,

the PWM maximum resolution is 1.3 ns.

The STLUX family has 6 SMEDs available. Multiple SMEDs can operate independently from

each other or they can be grouped together to form a more powerful state machine.

The STLUX also integrates a low power STM8 microcontroller which is used to configure

and monitor the SMED activity and to supply external communication such as the DALI. The

STM8 controller has full access to all the STLUX subsystems, including the SMEDs. The

STLUX family also features a sequential ADC, which can be configured to continuously

sample up to 8 channels.

Section : Block diagram illustrates the overall system block and shows how SMEDs have

been implemented in the STLUX architecture.

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