Espressif launched ESP8266 in 2014 and ESP32 in 2016. ESP8266, with its Wi-Fi-only MCU, facilitated simple connectivity use-cases. ESP32 addressed use-cases that required dual-connectivity (Wi-Fi + Bluetooth/Bluetooth LE), considerably more computing power, and strong security features.
These two chips became segment leaders in the IoT market, powering up a large number of connected devices. In the meantime, the IoT market has not only become mainstream, but it has also matured in terms of features and cost expectations.
Espressif understands that it now has to strike a fine balance between features and cost. The one-size-fits-all model is no longer viable and there should be multiple products for various needs. With this in mind, the company is introducing ESP32-C3, which attempts to address the most common needs for connected devices.
Here are the key criteria that have been considered for the design of ESP32-C3:
1. Security. Even the lowest-cost connectivity solution needs to provide an appropriate level of security for common security threats.
2. Bluetooth Low Energy availability. Useful for improving user experience and field diagnostics.
3. Cost. An important parameter, particularly in terms of the availability of sufficient memory for common use-cases.
ESP32-C3 is a single-core, 32-bit, RISC-V-based MCU with 400KB of SRAM, which is capable of running at 160MHz. It has integrated 2.4 GHz Wi-Fi and Bluetooth LE 5.0 with long-range support.
Additionally, it has 22 programmable GPIOs with support for ADC, SPI, UART, I2C, I2S, RMT, TWAI, and PWM.
With a large variety in the use-cases and their memory requirements, it is tricky to determine the most suitable memory size for the SoC. However, it’s also important to support use-cases with one or, sometimes, two TLS connections to the cloud, which are Bluetooth-LE-active all the time.
ESP32-C3’s 400 KB of SRAM can meet these requirements, while still keeping the chip’s cost within the budget target. It offers dynamic partitioning for the instruction (IRAM) and data (DRAM) memory. The Bluetooth subsystem’s memory requirements are also optimized, in comparison with the ESP32.
Typically, connected devices use Wi-Fi connectivity to connect to cloud services. However, Wi-Fi-only devices pose some difficulty to the network configuration of the devices, as these devices fail to provide reliable configuration feedback to the provisioner, while at the same time iOS and Android provisioners have additional complexity when connecting to the network.
The availability of Bluetooth LE radio in the device makes the provisioning easy. Also, Bluetooth LE provides easy discovery and control in the local environment.
Previous versions of the Bluetooth LE protocol had a smaller range, and that made it not very suitable a protocol for local control in large spaces, e.g. big homes. ESP32-C3 adds support for the Bluetooth LE 5.0 protocol, with coded PHY and extended advertisement features, while it also provides data redundancy to the packets, thus improving the range (typically 100 meters).
Furthermore, it supports the Bluetooth LE Mesh protocol. This makes it a strong candidate for controlling devices in a local network, and for communicating with other Bluetooth LE 5.0 sensor devices directly.
To read more about the ESP32-C3, including its security capabilities, click here.
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