Apple Watch is the world’s most celebrated gadget in 2015. At the same time, however, early product reviews highlight some issues about slow apps, less than impressive user experience, and short battery life.
Apple, the master of artful integration, has done well for its reputation of elite hardware and has been able to create a sophisticated product design for a wearable device. But here is a design avenue that can help counter the challenges like slower apps and battery drain. The idea can serve well to Apple Watch 2 design that is most likely on the drawing board right now and countless other smart wearables in the making.
Apple S1 comprises of 30 components
The design consideration is based on value points taken from the recent launch of CEVA’s RivieraWaves Wi-Fi IPs that allow system-on-chip (SoC) engineers to integrate Wi-Fi functionality onto their chips with clear and visible power and size benefits. CEVA has unveiled its Wi-Fi and Bluetooth solutions for mobile, wearable and IoT devices at the Linley IoT Conference held in Santa Clara, California on June 11, 2015.
The CEVA RivieraWaves Wi-Fi platform encompasses MAC and PHY modem functions. The MAC device—available as a hardware accelerator as well as software stacks in the form of lower MAC and upper MAC—is processor and operating system (OS) agnostic. For the modem, there are two options available, hardwired modem and software-defined modem (SDM).
Apple Watch Design Revisit
Let’s revisit the Apple Watch design footprint S1 that comprises of 30 components. Apple’s revered smart watch uses Bluetooth to connect to the iPhone and Wi-Fi to speed up data transfer when required. A sneak peek of S1 teardown from Chipworks shows that Apple used Broadcom’s BCM43342 chip for 802.11n, Bluetooth 4.0 and FM communication functions. The view of teardown also shows that Broadcom’s Wi-Fi plus Bluetooth combo IC is the second largest chip on the Apple Watch footprint. It acquired the die size of 18.5mm2 on S1.
Broadcom’s Wi-Fi chip is the largest after Apple’s APU
Now let’s take CEVA-plus-Catena-RF 802.11ac and Bluetooth combo solution that comes with MAC, modem, AFE, RF, CPU and memories. CEVA has joined hands with Catena, a supplier of RF IPs, to provide one-stop-shop for Wi-Fi and Bluetooth IP solutions. Catena’s radio IPs for Wi-Fi and Bluetooth are available on a number of process nodes, including 28nm at GlobalFoundries and 65nm at TSMC.
The CEVA-plus-Catena-RF solution, integrated with Apple’s APL0778 application processor manufactured at 28nm, would have taken up just 6mm2 on Apple S1, resulting in a 70 percent saving in die size. And that’s a lot of leverage in terms of power consumption and reduced cost due to smaller die size and lower BOM. The reduction in power consumption for the Wi-Fi plus Bluetooth connectivity stack on Apple’s SoC would have also come from the lower geometry of Apple app processor manufactured at 28nm. Broadcom’s Wi-Fi chip, on the other hand, has been manufactured at 40nm.
The CEVA RivieraWaves IP platform allows chip designers to integrate Wi-Fi connectivity onto their SoC solutions. The Wi-Fi integration is becoming imperative for wearable and Internet of Things (IoT) devices in particular because these devices are all about being smaller, cheaper and low-power. Moreover, Wi-Fi consumes lower power than Bluetooth for higher data transfer as shown in the Apple Watch use-case.
Wi-Fi integrated into APU or MCU
Another option that CEVA offers is a low-cost standalone Wi-Fi chip design that doesn’t require a host application processor. Here, CEVA’s TeakLite-4 DSP core can execute CPU functions. The CEVA-TeakLite-4 takes care of MAC and TCP/UDP protocol stacks and provides support for always-on sensing and audio processing applications.
CEVA’s MAC device is processor agnostic, so chip designers are free to pick other CPUs such as ARM Cortex-M, Andes, Cortus APS and ARC EM platforms.
A CEVA-powered Wi-Fi chip that doesn’t require a CPU license
Beken Design Win
Beken Corp., a high-volume supplier of wireless audio chips, has licensed the CEVA TeakLite-4 DSP core and RivieraWaves Sense 802.11n Wi-Fi connectivity solution for its upcoming SoC designs.
CEVA offers three connectivity platforms to cover all bases in the rapidly expanding Wi-Fi world. The RivieraWaves Sense IP for 802.11a/b/g/n/ac boasts the lowest power and smallest footprint that makes its suitable for wearable and IoT devices. The RivieraWaves Surf IP—aimed at mobile devices like smartphones and tablets—offers 802.11ac 1×1 and 2×2 IPs.
The CEVA RivieraWaves Wi-Fi IPs come in three flavors
CEVA’s third Wi-Fi flavor, the RivieraWaves Stream, is the highest performance IP that caters to wireless infrastructure products such small cells and access points. It serves 802.11ac for up to 4×4 MIMO applications and uses the CEVA-XC DSP core to facilitate advanced wireless communications.
Apparently, the Shanghai, China–based audio chipmaker Beken has opted for the CEVA-TeakLite-4 DSP for merging the Wi-Fi, Bluetooth and audio functionality onto a single core in its wireless SoCs. The CEVA-TeakLite-4 DSP cores are designed to handle audio, voice, sensing and wireless connectivity applications and they do it without requiring an additional CPU.
Again, resorting to the smart watch example, a single Bluetooth-enabled CEVA-TeakLite-4 can run always-on voice activation and voice commands, sensor fusion functionality, audio/voice processing, and dual-mode Low Energy Bluetooth also known as Bluetooth Smart Ready.
Visit RivieraWaves Wi-Fi product page for more information on the CEVA RivieraWaves Wi-Fi IP platform.