AN2786

STLED316S: serial interfaced LED controller with key-scan

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STLED316S: serial interfaced LED controller with

key-scan

The device used for the washing machine user interface is a compact LED controller and

driver. It interfaces with the MCU through a simple 3-wire serial interface.

The STLED316S drives up to 56 LEDs connected in a common anode configuration.

Individual digits may be addressed and updated directly, without re-writing the entire display

panel.

Additionally, the STLED316S includes key scanning for an 8x2 key matrix, which

automatically scans a matrix of up to 16 keys.

Figure 1.

Product application diagram example

The STLED316S is equipped with an internal display RAM memory to store the data

transmitted from the MCU through the serial interface.

The device is programmed through a variety of read/write commands that permit the user to

set the display panel and manage the keyboard.

To avoid scanning the keyboard repeatedly searching for a pressed key, an additional IRQ

signal can be connected to the MCU. An interrupt is generated whenever a key is pressed.