I/O stands for input/output, or the process by which information is transmitted to a computer and the process by which the computer interacts with the physical world. Given the increasing number of sensors, actuators and peripherals in today’s vehicles — each of which drives an I/O requirement on the controllers that support them — I/O is becoming an increasingly important area of emphasis in next-generation vehicle architectures.
In the IT world, common input devices are keyboards, mice, microphones and webcams — in other words, devices that allow people to input data to a computer. Examples of output devices are monitors, printers, speakers, sound cards and video cards. There are also devices that have both input and output functions, such as hard drives, network interface cards and modems.
In the industrial world, input devices are pressure gauges, thermometers and other types of sensors, while output devices are the control valves and other physical systems that respond to the information provided by the input devices.
Input data is often transmitted via a bus (the hardware and software that makes up the communication system), and output activities are typically coordinated by a controller.
I/O in the automotive world
Vehicles are currently undergoing a rapid increase in I/O, unlike anything seen previously in the automotive industry. This is leading to high levels of complexity that require new approaches to electrical and electronic architecture, such as Aptiv’s Smart Vehicle Architecture™ (SVA™).
Consider the number of input devices in an automotive scenario, allowing controllers to receive input not just from the human occupants, but also from the vehicle itself, the environment around the vehicle and wireless communications networks.
Common examples of human inputs include the buttons or touchscreens that allow occupants to turn up the heat, play music, adjust the seat position, roll down the windows, and so forth — and moving forward, inputs will increasingly come through microphones and cameras for features such as voice and gesture control. Some inputs will come from the occupants without them having to take actions, such as the Passive Occupant Detection System (PODS) that detects someone sitting in a seat or the driver state sensing system that determines whether the driver is alert and in a driving position.
But the vehicle systems also receive other inputs ranging from the traditional to the cutting edge. For example, vehicle inputs include sensors measuring temperature, fuel level and tire pressure, but increasingly vehicles are adding environmental inputs from radars, cameras, lidars and ultrasonic sensors that connect directly to a domain controller. Inputs from wireless communications are also on the rise, from well-established wireless key fobs, to cellular and Wi-Fi support for over-the-air (OTA) software updates from the cloud, cellphone connections and vehicle-to-everything (V2X) communications.
Outputs in an automotive scenario include the systems that perform required actions, from the actuator that makes the window roll down, to the braking system that stops the vehicle when the automatic emergency braking system engages, to the steering system that keeps a vehicle in its lane or guides the vehicle during automated parking. Outputs also include comfort features such as the air conditioner, the seat heaters and cabin lighting. They include any communications with the driver and other humans, from lane-change signals and indicator lights to the internal speakers.
Infotainment is a complex system that involves both input and output in a single device. Input is received when users touch the screen, and output is the information displayed on the same screen.
The challenge for OEMs is that all these inputs and outputs are being added at once, and space within a vehicle’s chassis is finite. In the past, each new feature has required its own electronic control unit (ECU), and each ECU would have its own I/O connections. This approach will not scale, and it is too complex.
Separating I/O from compute
Aptiv’s SVA divides the vehicle into discrete zones and deploys multiple zone controllers that are connected to each I/O device in that zone. The zone controller helps manage the I/O in a much more efficient and cost-effective manner, performing local data transformation, aggregating the data and putting it onto a single high-speed cable that connects to the vehicle’s domain controller or central computer.
This decoupling of I/O from compute provides multiple benefits. Delivering power and data connections to the sensors and other devices with just a backbone connection to the domain controllers improves scalability and reduces physical complexity.
In addition, once I/O is separated from compute, resources can be allocated to various software applications dynamically, as needed, based on priority and need. This approach allows the sharing of resources among physically separate domain controllers, so they can operate logically as one. And this approach supports mixed criticality, where processing power is prioritized for safety features over less critical functions such as infotainment.
Finally, Aptiv’s SVA not only reduces complexity and lowers costs for OEMs. The approach also provides a platform for innovation by giving OEMs the ability to fully control the software that defines the user experience of their vehicles and to enhance that functionality via continuous software release cycles.