ST AEKD-STEREOAVAS Manuale utente
Introduction
Electric cars, hybrid cars, and fuel cell vehicles not only help to protect the environment, but they also provide a better quality of
life in urban and rural areas. The innovative, whisper-quiet drive technologies can increase the risk of accidents under certain
circumstances. The acoustic vehicle alerting system (AVAS) provides added safety wherever the noise of electric motors, which
is too quiet, can become a hazard.
The AVAS simulates the engine noise of a combustion engine in the lower speed range to improve the safety of vulnerable road
users (VRUs) such as pedestrians, cyclists, and children. Artificial vehicle sounds are generated using loudspeakers or
actuators through the vibration of the vehicle structural elements proportional to vehicle parameters such as velocity, gas pedal
position, and gear. Electric cars are barely audible, especially at low speeds, and can pose a safety risk. AVAS is a significant
contribution to road safety. If a vehicle with alternative drive technology moves to a higher speed range, the rolling noise of the
tires on the road is sufficient and AVAS is automatically deactivated. AVAS can be fitted not only on passenger cars, but also
commercial vehicles and vehicles such as buses and garbage trucks.
Since July 2021, all new vehicle models registered in the EU must be equipped with an acoustic warning system as a
mandatory requirement under EU Decision ECE R138. If a too-quiet car is traveling in traffic at a speed of less than 20
kilometers per hour, the acoustic warning system must give a signal. At speeds above 20 kilometers per hour, the audible
warning system for electric vehicles automatically deactivates. In the US, the threshold is 19 mph (30 km/h).
Our AEKD-STEREOAVAS is an AutoDevKit acoustic vehicle alerting system (AVAS) demo.
It consists of an AEK-AUD-C1D9031 compact AVAS board, an AEK-MCU-C4MLIT1 domain controller, and two AEK-LCD-
DT028V1 display expansion boards, plus two loudspeakers and a switching button.
The AEK-AUD-C1D9031 communicates with the AEK-MCU-C4MLIT1 via CAN protocol, exchanging commands like start/stop to
simulate alerting sounds used in e-vehicles. The sound is reproduced by the AEK-AUD-C1D9031 ECU through a pair of
integrated loudspeakers.
Two AEK-LCD-DT028V1 boards with resistive touch allow the user to interact with the demo. The first screen shows a graphic
simulation of the tachometer, while the second allows starting/stopping the demo and regulating the sound volume and the
engine rpms.
Warning: The AEKD-STEREOAVAS evaluation kit has not to be used in a vehicle as it is designed for R&D
laboratory use only.
Figure 1. AEKD-STEREOAVAS evaluation kit
Getting started with the AEKD-STEREOAVAS integrated stereo AVAS solution
UM3214
User manual
UM3214 - Rev 1 - July 2023
For further information contact your local STMicroelectronics sales office. www.st.com
1 Hardware overview
1.1 Kit main components
1. AEK-AUD-C1D9031 compact AVAS board
2. Integrated loudspeakers
3. Disconnect speaker switch
4. AEK-MCU-C4MLIT1 domain zone controller board
5. AEK-LCD-DT028V1 display expansion board with resistive touch that shows a graphic simulation of the
tachometer
6. AEK-LCD-DT028V1 that allows starting/stopping the demo and regulating the sound volume and the engine
rpms
Figure 2. Kit components
2
3
1
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1.1.1 AEK-AUD-C1D9031 overview
1. SPC582B60E1 automotive microcontroller
2. Class D FDA903D power amplifiers
3. CAN connector
4. Hardware mute switch
5. Turn on/off sound button
6. Connector compatible with AEK-AUD-C1D9031
Figure 3. AEK-AUD-C1D9031 components
The AEK-AUD-C1D9031 represents the core of our solution.
It is a very compact AVAS solution based on SPC582B60E1 Chorus family MCU and FDA903D Class D audio
amplifiers that emits warning sounds to alert pedestrians of the presence of e-vehicles in the proximity.
The optimized board size allows installation of more than one AVAS module in an e-car to ensure that the warning
sound is heard in any direction along the vehicle.
The board hosts the SPC582B60E1 automotive microcontroller belonging to the Chorus family, embedding a high
performance e200z2 single core 32-bit CPU with 80 MHz clock, 1088 KB Flash and 96 KB SRAM, in a compact
eTQFP64 package.
The microcontroller monitors and controls the two Class D FDA903D power amplifiers driving the loudspeakers.
The audio transmission from the microcontroller to the two audio amplifiers is implemented via I²S interface
(simulated by an SPI peripheral), while I²C port and GPIOs are used to provide the necessary signals and
communication lines to configure the power amplifiers.
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The proposed AVAS solution is designed to be remotely controlled by a central ECU via CAN interface, using the
on-board CAN connector. The board also features a hardware mute button and a button to turn on/off the sound.
In addition, a connector is present to plug a board with two sliders: one to manage the speed (engine rpm) and
the other to manage the volume. A compatible version of these sliders is included in the AEK-AUD-C1D9031.
For further information on this board, refer to the related user manual.
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1.1.2 AEK-MCU-C4MLIT1 overview
The AEK-MCU-C4MLIT1 represents the domain controller of our solution. It is designed to address automotive
and transportation applications requiring automotive safety and security levels.
The board exploits the functionality of SPC58EC80E5 32-bit automotive grade ASIL-B microcontroller with 4 MB
flash, full access to the two MCU cores, GPIOs and peripherals such as ISO CAN FD (with transceiver) and
UART at a very competitive price. The board hosts a PLS debugger/programmer and an extension connector
(4x37 pins) for functional interaction across boards that are compatible with the AutoDevKit ecosystem. The PLS
Universal Debug Engine (UDE) software is available for free download and includes a free perpetual 256 Kbyte
debugging/programming license.
Figure 4. AEK-MCU-C4M1LIT1 MCU board
SPC58EC80E5
(Chorus 4M)
MCU
CAN interface
For further information on this board, refer to the related user manual.
1.1.3 AEK-LCD-DT028V1 overview
The AEK-LCD-DT028V1 display expansion board hosts a 2.8” LCD display with resistive touch (resolution of
240x320 pixels), managed by an on-board SPI touch screen controller.
The two LCD screens hosted in our solution show a graphical representation of a tachometer and the way it
changes according to the engine simulated rpm.
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Figure 5. AEK-LCD-DT028V1 display expansion board
Note that these LCD are based on low-cost touch-resistive technology. Therefore multi-touch or quick continuous
touches are not allowed.
At system start-up, to avoid hang-ups, make sure that the drawings are completed before using the touch screen.
For further information on this board, refer to the related user manual and to the LVGL libraries here https://
lvgl.io/.
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2 Software overview
Download the latest release of AutoDevKit Studio.
When you import an existing application in the tool, you can find a list of available demos.
The demos to be uploaded on the kit are two:
• one for the AEK-AUD-C1D9031, “SPC582Bxx_RLA_AEK_AUD_C1D9031 - Avas Compact - Test
Application”
• one for the AEK-MCU-C4MLIT1, “SPC582Bxx_RLA_MainEcuForAVAS Integrated - Test Application”
Both demos are already pre-loaded on the respective boards of the kit.
The first demo shows how to simulate the car engine sound, performing diagnostic in real-time, in two different
states: play and mute. The demo provides an example of how to manage the two FDA903D audio amplifiers with
a driver dedicated to an AEK-AUD-C1D9031 board. The detection of the open load in play mode depends on the
sound characteristics (refer to the FDA903D datasheet for details).
The board is ready to be tested. If you need to download the firmware again, use SPC5-UDESTK programmer
plugged on the JTAG connector. The source code is present from AutoDevKit 1.4.0. To upload the demo into the
microcontroller, refer to UM2719, Section 7.2.1 How to upload the demos for AEK-AUD-C1D9031.
To start and stop the sound, use the dedicated button. While in stop status, the LED D6 turns on. When the open
load fault is detected, LED D8 turns on, while LED D7 is turned on when pushing the hardware Mute button.
By default, this demo is controlled via CAN by an external MCU/ECU. It is possible to simulate the car engine
acceleration/deceleration using commands via CAN. The file CANCommunication.h under the source folder
contains the information (SID and Value) related to the messages managed by the demo.
You can find further details on the algorithm implemented to simulate the car engine sound and how to load the
sound on the microcontroller board in UM2719.
The second demo manages the inputs coming from the displays (for example, start and stop, accelerate,
decelerate, etc.) and sends the related CAN messages to the AVAS ECU.
At the same time, this demo can also manage diagnostic messages coming from the AVAS ECU. Refer to section
6 for more details.
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3 How to upload the demos for AEK-AUD-C1D9031
Follow the procedure below to import the demos into AutoDevKit Studio.
Step 1. Select [Import samples from application library] from the Common tasks pane. An Import application
Wizard appears.
Step 2. In the Import application Wizard, insert the appropriate product family details.
Step 2a. Import samples task button
Step 2b. Product family selection panel
Figure 6. AutoDevKit Studio Import application Wizard
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Step 3. Select the desired application from the library.
Step 3a. application selector
Step 3b. confirmation buttons
Figure 7. AutoDevKit Studio application library
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4 How to use the solution
To start the demo:
Step 1. Connect a 12 V power supply.
Step 2. Switch the demo on through the power switch on the AEK-MCU-C4MLIT1.
Step 3. Press the start button on display 1 to reproduce the engine sound. Then, on display 2, press the left-
hand side buttons to regulate the volume and the right-hand side buttons to regulate the engine rpm.
Display 1 simulates a vehicle tachometer and it varies according to the rpm button pressure.
Figure 8. Operating the demo
Power supply
Power switch
1
2
Volume
buttons
Speedometer
simulator
Rpm
buttons
Power supply
Power switch
1
2
Volume
buttons
Speedometer
simulator
Rpm
buttons
To stop the demo, just press the stop button on display 2. In this scenario, the green LED (D6) on the
AEK-AUD-C1D9031 will light up.
Figure 9. Stopping the demo
LED D6 (green)
Important: The touch screen is resistive. Therefore multi-touch does not work To avoid hang-ups, make sure that
the action completes before touching the screen again.
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Indice
