Okay, we don’t mean to scare you, but do you remember the bad old days, when the back of your PC looked like this?
We do, too. But then USB came along, and within a few years everything was connecting to everything via a standard interface. These days even the built-in components of your laptop like your mouse and touchpad communicate to the main board through USB interfaces. How did the USB interface get its start? What’s next for it in this connected IoT age? Read ahead to find out.
The history of USB and how it works
In the mid-90s, the creators of USB saw a need to consolidate the pathways by which machines speak to each other (Machine to Machine or M2M). USB was so successful that today it is the default connection for everything from smartphones to mice to printers. Micro-USB and Mini-USB variants further expand the USB footprint. Under the covers of the PC, even the touchpad and built-in keyboard and other built-in peripherals of your laptop communicate with the device via USB.
Let’s step back and examine how USB functions so that we fully understand the implications of the technology as we progress to our next topic. It’s all about devices and hosts. The host, like a PC, initiates communication and provides power, while the device, like a mouse or other USB-connected peripheral, replies to what the host requests.
Perhaps one of the most useful aspects of the USB topology is its ability to provide power to a device. You know this if you’ve ever used a USB cable to charge your smartphone. How much power can you move over a USB interface? The standard is at least 100 mA of current, but it could take as much as 500 mA. Sounds like there should be no power issues at all, right? Unfortunately, because USB requirements depend so heavily on having a reliable main power supply connected to an outlet, like the PC itself. There’s where we run into problems with M2M interfaces like those in the Internet of Things.
USB in the age of IoT
There’s one big problem with USB when you’re using it for portable, battery-powered connected devices: it’s an energy hog. From the outset, when you’re working through your power budget, you have to make some hard choices to balance battery size and battery life. USB can blow through your power budget—but you still want to use USB because it’s a widely-adopted standard interface. You have a problem, and we have a solution.
When examining the evolution of the USB interface, it’s clear that the next step is to make USB the universal and power-friendly solution for battery-powered devices. MCUs like Silicon Labs EFM32 Happy Gecko make the minute decisions necessary to reduce power consumption dramatically, enabling USB to penetrate markets where it has not yet succeeded to its fullest potential.
Download the full whitepaper, “The Past, Present and Future of USB,” to learn more about how to incorporate USB into your designs with no compromises.