STMicroelectronics STEVAL-LLL002V1 User manual
Introduction
The STEVAL-LLL002V1 evaluation kit consists of the STEVAL-LLL002M1 main board and the STEVAL-LLL002D1 USB-UART
bridge.
It has been designed to test and evaluate ALED1262ZT performance.
The STEVAL-LLL002M1 is a LED array driver system evaluation board with local dimming and diagnostics for automotive
applications. It is based on the ALED1262ZT 12-channel LED driver controlled through the STM8AF6266 microcontroller I²C
interface.
A 48 red LED matrix is driven by four ALED1262ZT LED drivers.
The on-board A7986A DC-DC converter, accepting standard adapter input voltages with reverse polarity protection, provides
the voltages and power for the board operation.
The STEVAL-LLL002V1 evaluation kit jumpers simulate LED open circuit faults and the 4-pin SWIM connector is used to debug
and develop the STM8AF6266 microcontroller firmware.
The evaluation kit can operate in bus driven mode (BDM), standalone mode (SAM) and GUI mode.
In the bus driven mode, the board is controlled via on-board push buttons and potentiometers. Commands to the ALED1262ZT
driver are sent by STM8A microcontroller over I²C bus.
In the standalone mode, the STEVAL-LLL002V1 evaluation kit is not controlled by the MCU and you can select two possible
output configurations using OTP ½ SPDT switch (SW2).
In the GUI mode, the board is connected to a PC via USB-UART bridge and you can observe and control various features of the
driver through the graphical user interface.
Figure 1. STEVAL-LLL002V1 evaluation kit
Getting started with the evaluation kit for automotive rear lights with pattern
animations based on ALED1262ZT and STM8AF6266
UM2381
User manual
UM2381 - Rev 1 - June 2019
For further information contact your local STMicroelectronics sales office.
www.st.com
1Hardware description
1.1 STEVAL-LLL002M1 main board
The STEVAL-LLL002M1 evaluation board includes four ALED1262ZT LED drivers, an 8-bit automotive grade
MCU, a SWIM connector to program the MCU, 48 red LEDs, push buttons to switch modes, and potentiometers
to control brightness and speed.
The on-board A7986A DC-DC converter, accepting standard adapter input voltages (12 – 24 V), provides the
voltages and power for the board operation.
Figure 2. STEVAL-LLL002V1M main board (top side)
Figure 3. STEVAL-LLL002V1M main board (bottom side)
1.1.1 Chip select (CS) one time programming (OTP)
The STEVAL-LLL002M1 evaluation board has four ALED1262ZT drivers.
The ALED1262ZT LED driver is provided with five one time programming (OTP) memory cells that can be
programmed to provide a permanent address to the device, creating a total of 32 driver addresses, that is, at a
given time, a maximum of 32 drivers can be connected to the to the MCU via I²C bus.
Table 1. STEVAL-LLL002M1 evaluation board: ALED1262ZT addresses
ALED1262ZT WRITE READ
Default 0x40 0x41
LED driver - U4 0x42 0x43
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Hardware description
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ALED1262ZT WRITE READ
LED driver - U5 0x44 0x45
LED driver - U6 0x46 0x47
LED driver - U7 0x48 0x49
On-board J2 is used to select the ALED1262ZT device for OTP. The LED driver is given a particular command
over I²C providing 18 V (±1 V) to be applied at the corresponding chip select (CS) pin.
Note: For more information please refer to the ALED1262ZT datasheet on www.st.com.
1.2 STEVAL-LLL002D1 USB-UART bridge
The STEVAL-LLL002V1 evaluation kit is also equipped with a USB-UART bridge for the communication between
PC and microcontroller.
Figure 4. STEVAL-LLL002V1D (top side)
Figure 5. STEVAL-LLL002V1D (bottom side)
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STEVAL-LLL002D1 USB-UART bridge
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1.3 Evaluation kit block diagram
Figure 6. STEVAL-LLL002V1 block diagram
1.4 STEVAL-LLL002V1 key devices
The STEVAL-LLL002V1 main devices are:
•A7986A: a high efficiency step down 250 kHz (programmable up to 1 MHz) switching regulator with max. 3 A
DC output current. Input voltage varies from 4.5 to 38 V and also depends on the required output. It supports
low dropout operation along with zero load current operation. Overcurrent and thermal protection are
provided for safe board operation. It powers the red LEDs.
•LM2931: an AEC-Q100 qualified 100 mA LDO regulator designed for automotive environments.
•STM8AF6266: an automotive grade 8-bit microcontroller, featuring 10 MIPS at 16 MHz CPU, advance
timers, UART, ADC, robust I/O's, nested interrupt controller.
•L78L33ACUTR: a three terminal positive regulator. It gives output current up to 100 mA and output voltage
of 3.3 V. The L78L series uses as Zener diode/resistor combination replacement, resulting in a lower
quiescent current and lower noise.
• Diode bridge: at the power supply input ensures board operation regardless of the input voltage polarity.
• 48 red SMD LEDs mounted in a 12x4 matrix to display different patterns. The minimum luminous intensity of
a LED is around 3.55 cd with wide viewing angle of 120º and wavelength of 623 nm.
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Evaluation kit block diagram
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2STEVAL-LLL002V1 connections
2.1 Power supply
The STEVAL-LLL002V1 evaluation kit is powered by standard 12–24 V DC power adapter.
The power source must deliver sufficient current depending on the input voltage for proper functioning.
Reverse voltage protection and input surge protection are provided to avoid any damage.
2.2 Microcontroller SWIM
The STEVAL-LLL002V1M board is equipped with a standard 4-pin SWIM connector allowing to debug and
develop the STM8AF6266 microcontroller firmware.
2.3 Jumpers for LED open-circuit simulation
LED errors can be simulated by using J5 to J8 jumpers.
Removing a jumper on J5, J6, J7 and J8 causes LED open-circuit error in D48, D49, D50 and D51 respectively.
These simulated errors can be detected in error detection mode: the defective LED is signaled by lighting the
adjacent LED on the board in standalone mode, and by flashing the corresponding light in the LED map in GUI
mode.
2.4 USB-UART bridge
The STEVAL-LLL002V1 communicates with the GUI via the USB-UART board, which acts as the bridge between
STM8AF6266 and your PC.
It communicates with the main board via UART interface and with PC via USB.
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STEVAL-LLL002V1 connections
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3Operation modes
3.1 Bus driven mode
In this mode, STEVAL-LLL002V1 is controlled via on-board push buttons and potentiometers.
Commands to the ALED1262ZT LED driver are sent by STM8AF6266 microcontroller through I²C interface.
After DC input is applied for the first time, the board goes into free running mode and displays all patterns and
modes, one after another.
You can exit from this free running mode using the BCK or FWD button.
3.1.1 Features
In bus driven mode, the board features:
•Pre-configured patterns (with adjustable brightness/speed) as rolling text, wave effect, super car scanning,
dot sequence, etc.
• On-board push buttons to switch between the demos
• Potentiometers as sliders to control the pattern speed or brightness
• Open circuit error simulation using open circuit jumpers (J5-J8)
• Jumper to switch from bus driven mode to standalone mode (J4)
• OTP ½ switch (SW2) to choose between two different predefined pattern in SAM mode
3.1.2 Normal mode
The STEVAL-LLL002V1 evaluation kit enters the bus driven mode (BDM) when powered.
In this mode, the MCU sends data over I²C bus to the ALED1262ZT LED driver.
Note: To operate in BDM mode, jumper J4 should be placed.
The bus driven mode main controls are:
• Push-buttons for transition among different demos:
– BCK button: to switch on the previous pattern or mode
– FWD button: to switch on the next pattern or mode
• Potentiometers:
– Brightness and speed control: on rotating potentiometer clockwise/anticlockwise, brightness/speed
among transitions increases/decreases.
• Open circuit error detection to detect LED failure
Note: On powering up, the evaluation board goes into free running mode displaying pattern changes after a fixed
interval of time. You can exit from this mode by pressing FWD or BCK push buttons.
The evaluation board displays different patterns in BDM:
1. Dot Sequence Rail
2. Back Light (all LEDs on)
3. Super Car Scanning Effect - I
4. Alphanumeric Flashing
5. Super Car Scanning Effect - II
6. Alphanumeric Rolling
7. Animation – 3D
8. Horizontal Wave
9. Pattern – I
10. Vertical Wave
11. Diagonal Wave
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Operation modes
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12. Pattern – II
13. Error Detection
Note: In Alphanumeric Flashing Pattern, you can control the speed only.
In Super Car Scanning Effect – I, Super Car Scanning Effect – II, Animation – 3D, Pattern – I and Pattern – II
you cannot control brightness as the ALED1262ZT PWM (7-bit individual channel control) feature is enabled.
3.1.3 Error detection
ALED1262ZT driver is capable of detecting error for open circuit.
The STEVAL-LLL002V1 evaluation kit provides the option to simulate and detect errors by entering the error
detection mode using FWD or BCK buttons.
Removing jumpers J5, J6, J7 and J8 causes LED open circuit error in D48, D49, D50 and D51 respectively.
The defective LED is signaled by switching on the adjacent LED.
Table 2. STEVAL-LLL002V1 error detection mode
Jumper Error in LED Shown on LED
J5 D48 D44
J6 D49 D45
J7 D50 D46
J8 D51 D47
Figure 7. STEVAL-LLL002V1 evaluation kit: error detection mode (J6 and J7 removed)
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Bus driven mode
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3.2 Standalone mode (SAM)
The STEVAL-LLL002V1 enters the SAM mode when the driver supply falls belows 3 V (removing jumper J4 that
is disconnecting the ALED1262ZT LED driver).
In standalone mode configuration, the device is not controlled by the MCU or a controller board.
You can select two possible output configurations using OTP ½ SPDT switch (SW2).
Figure 8. STEVAL-LLL002V1 evaluation kit: standalone mode (configuration 1)
Figure 9. STEVAL-LLL002V1 evaluation kit: standalone mode (configuration 2)
3.2.1 Features
The board enters the standalone mode by removing J4.
This mode mainly features:
•ALED1262ZT working without external controller
• Two different ouptus
• OTP ½ switch (SW2) to choose a configuration
3.3 GUI mode
The board can be connected to a PC through a USB-UART bridge using the graphical user interface (GUI) to
control and evaluate the ALED1262ZT driver features.
3.3.1 Features
All the bus driven mode features can also be controlled via GUI that manages also:
• Global brightness control to change the brightness of all the channels
• Frame programming mode and four predefined presets with variable transition time between frames
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Standalone mode (SAM)
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• Open circuit error detection in "no loop" and in 1 s and 2 s (approx.) loops
•Read/write configuration register
• Individual channel brightness control
3.3.2 GUI setup
To use the STEVAL-LLL002V1 GUI, you have to install the virtual COM port (VCP) driver on your PC/laptop by
following the procedure below.
Step 1. Install the .exe file on your PC.
The GUI appears in your program list.
Step 2. If the VCP driver is not installed, install it from ...\Program Files\ STMicroelectronics\LED Driver Demo
\ST VCP Driver. A 32-bit version and a 64-bit version are included in the setup.
On launching the GUI, the initial screen appears as shown below.
Figure 10. STEVAL-LLL002V1 evaluation kit: GUI initial screen
Step 3. Connect the STEVAL-LLL002M1 to the PC and power it up.
Step 4. Press [Connect].
The GUI identifies the board and automatically establishes a connection (COM3 is shown as an
example in the picture above), otherwise it prompts the user to select the port to which the board is
connected.
Step 5. If the GUI does not automatically identify the board, choose the port manually and press [Select].
When the GUI is able to interact with the board, a "Port is open” message is shown.
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GUI mode
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3.3.3 Modes
3.3.3.1 Basic mode
The STSW-LLL002GUI basic mode mainly features:
• Replication of on-board control buttons to select different modes from the GUI
• Buttons to enable/disable on-board push buttons
• Open circuit error detection with different frequencies
• Adjustable global brightness for all the channels
• Control registers write/read (BDM_Conf 1)
• Various flag status reading (BDM_status)
The basic mode has five sections to address different requirements:
• Button control
• Error detection
• Brightness control for all channels
• Configuration registers
• Individual channel ON/OFF control
Figure 11. STSW-LLL002GUI basic mode
3.3.3.1.1 Button control
The control buttons replicate the on-board BCK and FWD buttons and are used to toggle among preconfigured
demos.
The on-board buttons can be enabled or disabled by pressing [Enable] or [Disable] respectively.
3.3.3.1.2 Error detection
The error detection section demonstrates open circuit error (if any) present in the 12x4 LED matrix.
Error detection frequency can be selected from three options:
•No loop - error detection is performed just once and the results are displayed till any other button is pressed
• 1 second loop - error detection is performed every 1 s by the drivers and the results are updated in real-time
• 2 second loop - same as 1 second loop but error detection is performed every 2 s
3.3.3.1.3 Brightness control for all channels
Brightness of all the channels is simultaneously changed by varying brightness control for all channel slider.
Brightness can be varied in 256 steps (5% to 100%).
3.3.3.1.4 Configuration registers
The configuration register section represents two registers for the ALED1262ZT LED driver:
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GUI mode
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