Examples of IoT DDR Debug Scenarios

Figure 1: Using the oscilloscope's Track
math function can help pin down
timing anomalies

Our last post considered some broad aspects of debugging DDR memory on Internet of Things (IoT) devices, such as how chip interposers can help with probing access and the benefits of virtual probing software. Let's now take a look at some particular examples of problems with these memory chips and their controllers and see how debugging with an oscilloscope might be approached.

Debugging DDR Memory on IoT Devices

Figure 1: Embedded systems such as IoT devices often require
chip interposers to gain access to signal lines on DDR memory

Internet of Things (IoT) devices are, at heart, just another embedded computing system, albeit one with an extremely well-defined function. As such, there's bound to be some amount of on-board data storage, and the storage medium of choice these days is typically double data-rate (DDR) memory. DDR memory transfers serial data on both the rising and falling edges of the clock signal, which is the characteristic from which it derives its name.

Debugging Ethernet, SATA, and PCIe for IoT Devices

Figure 1: A generic IoT block diagram
shows serial-data links in blue

In our ongoing review of debugging serial-data standards for Internet of Things (IoT) devices, let's now turn to three more popular protocols: Ethernet, SATA, and PCIe. Ethernet is found in computer networking applications, while the Serial Advanced Technology Attachment (SATA) connects host bus adapters to mass-storage devices. The Peripheral Component Interconnect Express (PCI Express or PCIe) handles communication between root complexes (motherboards) and expansion-card interfaces.

Debugging CANbus For IoT Devices

Figure 1: Temperature data from
thermocouples is shown both
encoded and decoded on the
oscilloscope's display

A myriad of serial-data standards come into play when we're discussing Internet of Things (IoT) devices. We've talked about I2C, SPI, and UART in a previous post. Yet another serial-bus standard that comes under the IoT umbrella is the Controller Area Network (or CANbus) standard. CANbus enables microcontrollers and peripheral devices to communicate with each other in applications without an intervening host computer. In the past, it's been typically used in automotive applications, but CANbus has found its way into a wider scope of applications of late.

Debugging Low-Speed Serial Data on IoT Devices

Figure 1: Serial-data links handle traffic between ICs
and peripheral devices in the IoT world

Our last post discussed the difficulties in acquiring the many sensor signals that may be input to a deeply embedded system such as an IoT device as well as a hardware solution to the problem. Another aspect of IoT debugging and validation is the low-speed serial data standards used to facilitate communication between ICs and between controllers and peripheral devices (Figure 1). To that end, let's take a look at three such low-speed standards: I2C, SPI, and UART.

Acquiring and Characterizing IoT Sensor Signals

Figure 1: IoT devices use many sensors to collect data
about their ambient environment

If we recall our earlier post with its definition of what constitutes an Internet-of-Things (IoT) device, one of the main functions of such devices is to sense its environment and digitize the collected data. Often, an IoT device uses many sensors to collect information about its environment (Figure 1). Having the ability to capture and analyze signals from numerous sensors simultaneously is critical to ensure proper and optimal functionality of the IoT device's design.

Investigating IoT Wireless Signals (Part II)

Figure 1: This screen capture depicts frequency demodulation
and subsequent Manchester decoding of the bit stream

Internet of Things (IoT) devices must communicate with their peers--other IoT devices--as well as with the host system that governs their activities. In our previous post, we examined how to perform amplitude and frequency demodulation of RF bursts, such as Bluetooth Low Energy (BLE) advertising bursts. We'll continue with other methods of analyzing RF signals.

Investigating IoT Wireless Signals

Figure 1: Many IoT devices accept
wireless antennas using U.FL
connectors

Many IoT devices use wireless methods to communicate with other devices or with host systems. Just as with DC power-rail signals, probing of RF signals should be done with as little noise and as non-invasively as possible and with the best possible signal fidelity. Effective probing opens the door to Wi-Fi and Bluetooth signal analysis with RF demodulation, vector signal analysis, and spectrum analysis.

IoT Digital Power Management and Power Integrity

Figure 1: The half-bridge output
current from each DC-DC phase
is known as the inductor current

An Internet of Things (IoT) device derives its power either from a 12-V DC supply or from a battery. In either case, power is fed to one or more power rails that operate at different voltages. These rails power the CPU and other functional blocks on the PC board. In this post, we'll take a look at how to examine an IoT's power supply for proper digital power management implementation and for power integrity.

Anatomy of an IoT Device

Figure 1: IoTs include SOCs, DDR,
DPM ICs, wireless, and MCUs

There's already more Internet of Things (IoT) devices deployed than there are humans on Earth. That gap will increase radically in coming years, and the explosion in IoT devices means a commensurate explosion in the need for debugging tools. So what's in an IoT device to debug, anyway?

Debugging the IoT

Figure 1: Chances are you're already
using the IoT in various ways

By now, we're all familiar with the phrase "Internet of Things" (IoT); some of you may be directly involved with that concept on some level as a designer/technologist. Here, we'll begin a series of posts on the IoT with some broad discussion of what it's all about, and then segue into how oscilloscopes and related hardware/software are among the best tools available for design and debug of IoT-related devices.

Are You Ready for Bluetooth 5?

The Bluetooth Special Interest Group, which is the body that oversees the protocol's specification, doesn't stand still but rather continues to develop and improve Bluetooth technology. With an eye toward building an accessible and interoperable Internet of Things (IoT), the next version of the Bluetooth specification—Bluetooth 5—is slated to appear by early in 2017 and as soon as this fall.