It seems that the folks at Espressif are doing their best to produce chips to fit every possible niche in the microcontroller-with-radio market, because here comes news of their latest chip bearing the ESP32 name: a single-core 96MHz RISC-V part with built-in IEEE 802.15.4 to support ZigBee 3.x and Thread 1.x. The ESP32-H2 is not the most powerful of the Espressif line-up, but it will find its place in home automation products and projects.
The ESP32-H2 joins a multitude of other IEEE 802.15.4 devices from manufacturers such as Microchip, ST, NXP, and Nordic in an increasingly crowded marketplace, so what can if offer that the others can’t? If previous ESP chips are anything to go by we’d expect it to compete on price as well as the obvious attraction for developers used to working with other Espressif products. We look forward as always to seeing what you do with it.
We’re always interested in the latest from the world’s semiconductor industry here at Hackaday, but you might be forgiven for noticing something a little familiar about today’s offering from Espressif. The ESP32-WROOM-DA has more than a passing resemblance to the ESP32-WROOM dual-core-microcontroller-with-WiFi module that we’ve seen on so many projects over the last few years because it’s a WROOM, but this one comes with a nifty trick to deliver better WiFi connectivity.
The clever WiFi trick comes in the form of a pair of antennas at 90 degrees to each other. It’s a miniaturised version of the arrangement with which you might be familiar from home routers, allowing the device to select whichever antenna gives the best signal at any one time.
We can see that the larger antenna footprint will require some thought in PCB design, but otherwise the module has the same pinout as the existing WROVER. It’s not much of a stretch to imagine it nestled in the corner of a board at 45 degrees, and we’re sure that we’ll see it appearing in projects directly. Anything that enhances the connectivity of what has become the go-to wireless microcontroller on these pages can only be a good thing.
The ATMegaZero ESP32-S2 is currently being funded with a campaign on GroupGets, and it’s a microcontroller board modeled after the Raspberry Pi Zero’s form factor. That means instead of the embedded Linux system most of us know and love, it’s an ESP32-based development board with the same shape and 40-pin GPIO header as the Pi Zero. As a bonus, it has some neat features like a connector for inexpensive SSD1306 and SH1106-based OLED displays.
Being able to use existing accessories can go a long way towards easing a project’s creation, and leveraging that is one of the reasons for sharing the Pi Zero form factor. Ease of use is also one of the goals, so the boards will ship with CircuitPython (derived from MicroPython), and can also be used with the Arduino IDE.
If a microcontroller board using the Pi Zero form factor looks a bit familiar, you might be remembering the original ATMegaZero which was based on the Atmel ATMega32U4, but to get wireless communications one needed to attach a separate ESP8266 module. This newer board keeps the ATMegaZero name and footprint, but now uses the Espressif ESP32-S2 to provide all the necessary functions.
If you’re a reader of Hackaday, then you’ve almost certainly encountered an Espressif part. The twin microcontroller families ESP8266 and ESP32 burst onto the scene and immediately became the budget-friendly microcontroller option for projects of all types. We’ve seen the line expand recently with the ESP32-C3 (packing a hacker-friendly RISC-V core) and ESP32-S3 with oodles of IO and fresh new CPU peripherals. Now we have a first peek at the ESP32-C6; a brand new RISC-V based design with the hottest Wi-Fi standard on the block; Wi-Fi 6.
There’s not much to go on here besides the standard Espressif block diagram and a press release, so we’ll tease out what detail we can. From the diagram it looks like the standard set of interfaces will be on offer; they even go so far as to say “ESP32-C6 is similar to ESP32-C3” so we’ll refer you to [Jenny’s] excellent coverage of that part. In terms of other radios the ESP32-C6 continues Espressif’s trend of supporting Bluetooth 5.0. Of note is that this part includes both the coded and 2 Mbps Bluetooth PHYs, allowing for either dramatically longer range or a doubling of speed. Again, this isn’t the first ESP32 to support these features but we always appreciate when a manufacturer goes above and beyond the minimum spec.
Welcome to the ESP32-C6
The headline feature is, of course, Wi-Fi 6 (AKA 802.11ax). Unfortunately this is still exclusively a 2.4GHz part, so if you’re looking for 5GHz support (or 6GHz in Wi-Fi 6E) this isn’t the part for you. And while Wi-Fi 6 brings a bevy of features from significantly higher speed to better support for mesh networks, that isn’t the focus here either. Espressif have brought a set of IoT-centric features; two radio improvements with OFDMA and MU-MIMO, and the protocol feature Target Wake Time.
OFDMA and MU-MIMO are both different ways of allowing multiple connected device to communicate with an access point simultaneously. OFDMA allows devices to slice up and share channels more efficiency; allowing the AP more flexibility in allocating its constrained wireless resources. With OFDMA the access point can elect to give an entire channel to a single device, or slice it up to multiplex between more than once device simultaneously. MU-MIMO works similarly, but with entire antennas. Single User MIMO (SU-MIMO) allows an AP and connected device to communicate using a more than one antenna each. In contrast Multi User MIMO (MU-MIMO) allows APs and devices to share antenna arrays between multiple devices simultaneously, grouped directionally.
Finally there’s Target Wake Time, the simplest of the bunch. It works very similarly to the Bluetooth Low Energy (4.X and 5.X) concept of a connection interval, allowing devices to negotiate when they’re next going to communicate. This allows devices more focused on power than throughput to negotiate long intervals between which they can shut down their wireless radios (or more of the processor) to extended battery life.
These wireless features are useful on their own, but there is another potential benefit. Some fancy new wireless modes are only available on a network if every connected device supports them. A Wi-Fi 6 network with 10 Wi-Fi 6 devices and one W-Fi 5 (802.11ac) one may not be able to use all the bells and whistles, degrading the entire network to the lowest common denominator. The recent multiplication of low cost IoT devices has meant a corresponding proliferation of bargain-basement wireless radios (often Espressif parts!). Including new Wi-Fi 6 exclusive features in what’s sure to be an accessible part is a good start to alleviating problems with our already strained home networks.
When will we start seeing the ESP32-C6 in the wild? We’re still waiting to hear but we’ll let you know as soon as we can get our hands on some development hardware to try out.
Thanks to friend of the Hackaday [Fred Temperton] for spotting this while it was fresh!
It’s always an event when we have Adafruit on the Hack Chat, and last time was no exception. Then, the ESP32-S2 was the new newness, and Adafruit was just diving into what’s possible with the chip. It’s an interesting beast — with a single core and no Bluetooth or Ethernet built-in, it appears to be less capable than other Espressif chips. But with a faster CPU, more GPIO and ADCs, a RISC-V co-processor, and native USB, the chip looked promising.
Among their other duties, the folks at Adafruit have spent the last six months working with the chip, and they’d now like to share what they’ve learned with the community. So Limor “Ladyada” Fried, Phillip Torrone, Scott Shawcroft, Dan Halbert, and Jeff Epler will stop by the Hack Chat to show us what’s under the hood of the ESP32-S2. They’ve worked on a bunch of projects using the chip, and they’ve taken a deep-dive into the chip’s deep-sleep capabilities, so stop by the Chat with your burning questions about low-power applications or anything ESP32-S2-related and ask away.
Plus, a late and exciting addition to the agenda: they’ll be talking about the recently released RP2040, the first custom chip from the folks at Raspberry Pi. We’ve already started talking about the Raspberry Pi Pico, the dev board that uses the chip, and Adafruit will share what they’ve learned about the RP2040 so far.
Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.
Since Espressif Systems arrived in our collective consciousness they have expanded their range from the ESP8266 to the ESP32, and going beyond the original WROOM and WROVER modules to a range of further ESP32 products. There’s a single-core variant and one that packs a RISC-V core in place of the Tensilica one, and now they’ve revealed their latest product. The ESP32-S3 takes the ESP to a new level, packing as it does more I/O, onboard USB, and an updated version of the two Tensilica cores alongside Bluetooth version 5. It’s still an ESP32, but one that’s more useful, and it’s worth a closer look because we expect it to figure in quite a few projects.
Espressif’s block diagram for the chip.
Sadly the data sheet does not seem to have been released, but we do have some tidbits to consider. Espressif are anxious to tell us about its “AIOT” capabilities thanks to the vector instructions in the EXTensa LX7 cores (PDF) that were not present in the previous model’s LX6. They claim that this will speed up software neural networks; this does have an air of marketing about it but we’ll withhold judgement until we see it in use. The new core certainly will offer a performance improvement across the board though, which should be of interest to all ESP32 developers. Meanwhile the ultra-low-power core that existing ESP32 developers will be familiar with remains.
Then there is that USB support, which appears in the feature block diagram but has little information elsewhere. It’s listed as USB OTG which raises the possibility of the ESP32 being the host, but what it should also bring is the ability to emulate other USB devices. We’ve seen badges mount as WebUSB devices using STM32 clones as peripherals for an ESP32, but in future these tricks should be possible on the Espressif chip itself.
Probably the most anticipated piece of the new device’s specification comes in the addition of 10 new I/O lines. This has historically been a weakness of the ESP line, that it’s an easy chip with which to run out of available pins. These extra lines will make it more competitive with for example the STM32 series of microcontrollers that have larger package options, and will also mean that designs can have more in the way of peripherals without the use of port expanders.
In summary then, the latest member of the ESP32 family delivers a significant and useful update, and brings some of the features first seen in the single core version to the more powerful line of chips. Sadly it doesn’t have the hoped-for on-chip RAM boost, but it brings enough in the way of new capabilities to be of interest. At the moment it doesn’t look like the ESP32-S3 is available to order, but we hope to have engineering samples soon and should be bringing you a hands-on report in due course.
Six years on from the emergence of the Espressif ESP8266 we might believe that the focus had shifted to the newer dual-core ESP32. But here comes a twist in the form of the newly-revealed ESP32-C3. It’s a WiFi SoC that despite its ESP32 name contains a RISC-V core in place of the Tensilica core in the ESP32s we know, and uses the ESP8266 pin-out rather than that of its newer sibling. There’s relatively little information about it at the time of writing, but CNX Software have gathered together what there is including a draft datasheet whose English translation is available as a Mega download. As with other ESP32 family members, this one delivers b/g/n WiFi and Bluetooth Low-Energy (BLE) 5, where it differs is the RISC-V 32 Single-core processor with a clock speed of up to 160 MHz. There is 400 kB of SRAM and 384 kB ROM storage space built in.
Why they are releasing the part as an ESP32 rather than giving it a series number of its own remains a mystery, but it’s not hard to see why it makes commercial sense to create it in an ESP8266-compatible footprint. The arrival of competing parts in the cheap wireless SoC space such as the Bouffalo Labs BL602 we mentioned recently is likely to be eating into sales of the six-year-old chip, so an upgrade path to a more capable part with minimal new hardware design requirements could be a powerful incentive for large customers to stay with Espressif.
We’re left to guess on how exactly the rollout will proceed. We expect to see similar developer support to that they now provide for their other chips, and then ESP32-C3 powered versions of existing ESP8266 boards in short order. It’s also to be hoped that a standard RISC-V toolchain could be used instead of the device-specific ones for current Espressif offerings. What we should not expect are open-source replacements for the blobs that drive the on-board peripherals, as the new chip will share the same closed-source IP as its predecessors for them. Perhaps if the PINE64 initiative to reverse engineer blobs for the BL602 bears fruit, we might see a similar effort for this chip.
