STEVAL-ILL029V2 STMicroelectronics, STEVAL-ILL029V2 Datasheet - Page 11

• Manufacturer Part Number: STEVAL-ILL029V2
• Description: BOARD & REF DESIGN
• Manufacturer: STMicroelectronics
• Series: -r

Specifications of STEVAL-ILL029V2

• Main Purpose: Touch Interface, LED Driver
• Embedded: Yes, MCU, 32-Bit
• Utilized Ic / Part: STLED325, STM8S, STMPE24M31
• Primary Attributes: 4 Digit 7-Segment LEDs, 8 Discrete LEDs, 8 Touch Pads, 8-Channel Touch Wheel
• Secondary Attributes: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

STLED325
3
3.1
3.2
3.3
Functional description
The STLED325 is a common anode LED driver controller which can be used to drive red,
green or blue LEDs as the current is adjustable through the external resistor. In the common
anode configuration, the digit outputs source the current to the anodes while the segment
outputs sink the current from the cathodes. The configurable output current can be used to
drive LEDs with different current ratings (red, green or blue). The brightness can be
controlled through the I
together in parallel to drive a single LED. In this case, two parallel current sources of equal
value drive a single LED. The external resistor value can be set accordingly to determine the
desired output current.
Soft-start limits the inrush current during power-up. The built-in thermal protection turns off
the display when the temperature exceeds 140°C with a small hysteresis of 15°C. The
display is blanked (LEDs are turned off or in high-Z state) on power-up.
Low power mode of operation
When not used, the STLED325 goes into low power mode of operation wherein the current
consumption drops to less than 1 mA. During this mode, the data configured is maintained
as long as the supply voltage is still present (the contents of the internal RAM need the
supply voltage to be present). Port configuration and output levels are restored when the
STLED325 is taken out of shutdown. For minimum supply current in shutdown mode, logic
inputs should be at GND or V
I
The interface is used to write configuration and display data to the STLED325. The serial
interface comprises of a shift register into which SDA is clocked on the rising edge of the
SCL after a valid start of communication. When communication is stopped, transitions on
SCL do not clock in the data. During this time, the data are parallel-loaded into a latch. The
8-bit data is then decoded to determine and execute the command.
For an overflow condition, if more bytes are written, then they are ignored whereas if more
bytes are read, then the extra bytes are stuffed with 1’s.
Initial power up
On initial power-up, all control registers are reset, the display is blanked and the STLED325
is in the low-power mode. All the outputs are in high-impedance state at initial power-up.
The SDA is pulled high by an external pull-up resistor. The display driver has to be
configured before the display can be used.
2
C serial interface
2
C interface as described later. The outputs can be connected
CC
Doc ID 17576 Rev 1
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Functional description
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