AN4460 datasheet(28/54 Pages) STMICROELECTRONICS

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User interface

AN4460

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DocID026129 Rev 1

User interface

7.1

Control buttons

The STEVAL-ILL057V1 demonstration board features three buttons, used to manually

change the dimming duty cycle. The buttons can be configured to operate in two different

ways and their behavior is controlled via the “ed” command. Holding a button causes its

action to continue.

Single channel dimming: when the “ed” command is OFF (“ed 0"), the buttons behave as

follows:



“LED CH SEL”: selects a channel. The new selected channel blinks once.



“INC”: increases the dimming duty cycle on the selected channel.



“DEC”: decreases the dimming duty cycle on the selected channel.

Multichannel dimming: when the “ed” command is ON (“ed 1"):



The button “LED CH SEL” is not used.



The button “INC” increases the dimming duty cycle on all channels.



The button “DEC” decreases the dimming duty cycle on all channels.

The three buttons are read by the ADC channel line 7.

7.2

Status LEDs

There are two status LEDs attached to the board:



Green LED (status): the green LED is active when the input power is correct and the

STLUX385A is running. The LED can also act as a firmware performance monitor and

show the CPU usage. The performance mode is enabled by the “vi” instruction (see

Section 7.3) and the LED toggles as follows:

–

LED ON: CPU running

–

LED OFF: CPU sleeping



Red LED (failure): the red LED is used to report an error or the intervention of

a protection to preserve the hardware. Once the red LED is ON, the only way to clear is

to use the “co” command (see Section 7.3).

7.3

Serial interface

This section describes the terminal interface line available on the STLUX385A firmware.

The serial line allows the configuration of the:



Working point of the LED channel



Current level



LED numbers



Dimming percentage

It also allows the device internal status to be inquired.

The STLUX385A command line interface is accessible via a standard terminal utility

installed on the user's PC.

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