The modern world is steadily adopting more naturalistic human-machine interfaces (HMI). We are now able to speak to smart speakers, as well as read from e-reader displays that look like their paper counterparts. Electronics are increasingly becoming a digital companion that we take with us, rather than systems tethered to a power outlet.
Powering this revolution requires multicore processors that can handle everything from understanding spoken commands, to audio playback, graphical displays and system control. Innovations in power management and security enable these chips to remain always on and deliver interactivity on demand while consuming little energy.
NXP is enabling these innovations with the i.MX 8ULP applications processor. By placing functions in separate power islands, the chip offers fine-grained power management. An island can operate at reduced speed and voltage to save power, switched off all the way, or turned completely on. Among the most power-hungry parts of the processor are the CPUs. To enable them to sleep and conserve power while allowing a system to remain responsive, the i.MX 8ULP processor pioneers the ability to hand off control of peripheral functions from a more-powerful application CPU to a lower-power control CPU.
Importantly, the i.MX 8ULP processor has the smarts to decide which parts of the chip are asleep, fully awake or somewhere in between at any moment. NXP puts power management under software control, supplying multiple power-management programs for developers to adapt as needed. Or, they can create their own, writing software to monitor the system state and to adjust the frequency and voltage of each island.
For our smart devices and connected applications to be secure, they must rely on hardware with security built in. The i.MX 8ULP processor embeds the NXP EdgeLock® Secure Enclave , a security-focused unit physically isolated from the rest of the SoC with its own CPU, ROM and RAM. The EdgeLock® Secure Enclave provides a trusted environment for executing security-critical functions, including i.MX 8ULP processor integrity protection, user data confidentiality and secure connections. In particular, EdgeLock® Secure Enclave is the prime avenue to meet NIST 8425 standards and obtain the upcoming U.S. Cyber Trust Mark for connected consumer products, or to support IEC 62443 standards for industrial control and automation systems. The Edgelock® Secure Enclave's battery-backed security module also enables features such as tamper and zeroization on security violations to enable multiple applications including point of sale.
Additionally, the i.MX 8ULP processor provides OEMs with ready-to-use configurations of cryptographic profiles that meet regional requirements. Combined with NXP’s EdgeLock® 2GO key management services, manufacturers can also securely provision i.MX 8ULP processor-based products with credentials in an untrusted factory or in the field and manage the credentials over-the-air through an end-to-end secure connection between the embedded EdgeLock® Secure Enclave and EdgeLock® 2GO cloud platform. The i.MX 8ULP processor is also part of the NXP EdgeLock® Assurance Program and has been PSA and SESIP Security Level 2 certified, which accelerates proof-of-compliance to security standards and regulations.
Check out our family of industrial and smart home PMICs. The PCA9460 family is designed to support the i.MX 8ULP family processor.
For systems that respond to voice commands, the i.MX 8ULP processor integrates a Cadence Tensilica Fusion DSP along with a digital mic input and an I2S port. The ultra-low power Fusion DSP operates alongside a power-efficient Arm® Cortex®-M33F CPU in the i.MX 8ULP processor’s real-time domain, as the block diagram shows. A large on-chip memory allows the DSP and CPU to work without powering up an external chip. The rest of the chip can also be powered off while these cores are active. For example, they can listen for a wake word, only activating the rest of the chip once it’s heard.
In addition to running the show when the rest of the chip sleeps, the real-time domain—as its name suggests—handles time-critical tasks. To aid in this, it also includes timers and a rich set of low-speed I/O to control other parts of a system.
The i.MX 8ULP processor’s application domain, by contrast, runs the main software. At the heart of the application domain is up to two 64-bit Arm® Cortex®-A35 CPUs. These energy-efficient cores run Linux or Android, the adaptable operating systems that propel everything from mobile phones to central controllers. Complementing the CPUs, the application domain also houses fast I/O controllers. An SDIO interface can connect to peripherals such as NXP’s IW416 dual-band, triple-radio solution. This provides 2.4 GHz and 5 GHz Wi-Fi, Bluetooth and Thread radios, making it ideal for systems connected to everything from Matter smart home networks to a corporate LAN.
The flex domain addresses multimedia and graphics functions and includes a fully featured GPU and a Cadence Tensilica HiFi4 DSP. Although GPUs are often associated with PCs, smartphones and gaming consoles that don’t prioritize power, NXP builds one into the i.MX 8ULP chip without compromising energy efficiency. Reflecting the i.MX 8ULP processor’s power-management philosophy, the GPU can turn on its 3D circuitry on demand, using only its 2D engine at other times to save power while keeping the screen updated.
The HiFi4 DSP helps even tiny smart speakers deliver thumping bass and tinkling high notes, running the spatial-audio algorithms that enable a small device to deliver an immersive audio experience. The HiFi4’s role isn’t limited to playback, however, while capturing audio, it can process sound recorded from a microphone array, isolating a voice from the background clutter. Developers can also employ the HiFi4 for AI functions, picking up where the Fusion DSP left off and running neural networks to recognize speech.
Complementing these processing elements, the flex domain also includes audio, camera and display interfaces. For systems needing displays that look like ink on paper, the i.MX 8ULP processor integrates an electrophoretic display controller (EPDC) to drive E Ink panels. Systems with colorful, interactive screens can use the processor’s other interfaces.
The i.MX 8ULP processor’s sophisticated power management and security features enable it to serve as the heart and brain of diverse system types. Imagine battery-powered medical wearables with voice enablement, where low power is extremely critical. When operating on small batteries, these designs can take advantage of the 8ULP processor’s DSPs and audio interfaces, interfaces to wireless chips and E Ink controller. Applications such as logistics tags or smart shelf labels are similar but don’t need the audio functions. Those designs can also power off the DSP and audio interfaces to optimize power consumption.
A smart thermostat would operate quite differently. Drawing on only the i.MX 8ULP processor’s real-time domain and 2D mode of GPU operation, it would continually monitor temperature and periodically update an LCD panel, displaying the current temperature, settings and time. Every ten minutes the application domain would briefly wake to send data to a cloud-based service so the power company and homeowner could monitor and manage the home. The homeowner would occasionally interact with it using a slick touchscreen interface; during these times, the 3D GPU and application CPUs would power up. Elsewhere in the home, a smart meter operating for long periods on battery power wouldn’t run an interactive application or need a display but would still collect energy usage data and transmit it periodically. Such a design could take advantage of the i.MX 8ULP processor’s low power and ability to connect to wireless chips.
As simple as these systems are, user responsiveness must be instantaneous for a good experience. They must appear to be always on, even when in a power-saving state. The i.MX 8ULP processor’s ability to shift the real-time domain from low-frequency operation to full performance, wake up the application domain and transfer control between domains helps systems save power and never miss a beat. Even a half-second to perk up can be too slow. Smart watches with voice control, for example, are always on, listening for the special word that jolts them into action. The Fusion DSP in the i.MX 8ULP processor’s real-time domain can handle this listening function while the rest of the chip sleeps. The HiFi4 DSP activates only during music playback, processing the music so that even a small speaker makes a kitchen sound like a concert hall.
The i.MX 8ULP processor elevates developers' computing and multimedia capabilities without sacrificing power. NXP delivers even more with the i.MX 8ULP processor, increasing application performance, adding DSPs to process audio and perform AI functions, providing software-defined power management and raising security to a new level.
The i.MX 8ULP processor is available now. For more product information, please visit the i.MX 8ULP processor page on NXP’s website.
Gayathri Easwaran is the director of product marketing in the BL SCE, in Austin TX. She holds a Master's degree in Electrical Engineering from Washington St. University, and also leads ACT!ON (Asia Cultural Team of NXP ). She is passionate about finding differentiating solutions to enable customers. In her free time she loves working on podcasts on various topics.
