The ESP32-C2 (ESP8684) ^[1] family is a series of microcontrollers developed by Espressif Systems. It's based on the RISC-V architecture and is designed to offer ultra-low-power and small size for various IoT (Internet of Things) applications. This family of microcontrollers has been designed to target simple, high-volume, and low-data-rate IoT applications, such as smart plugs and smart light bulbs. ESP32-C2 is also supported by Espressif’s AIoT Private Cloud platform, ESP RainMaker® and supports Matter, a smart-home connectivity protocol that runs on any IP-supporting network stack.

The ESP32-C2 microcontrollers come with several distinctive features:

• RISC-V Core: The ESP32-C2 is based on the RISC-V architecture, which is an open-source instruction set architecture (ISA). This is a departure from the ESP32 series' usual Tensilica Xtensa LX6 architecture.
• Connectivity: Like other ESP32 modules, the ESP32-C2 features built-in Wi-Fi and Bluetooth 5 LE connectivity. This allows it to connect to the internet and communicate with other devices over short distances.
• Low Power Consumption: ESP32-C2, like other ESP32 variants, supports low-power modes, which is crucial for battery-powered and energy-efficient IoT applications,
• Rich Peripheral Interface Support: It includes a variety of peripherals such as UART, I2C, SPI, ADC, and more, making it versatile for different applications.
• Security Features: The ESP32-C2 family includes various security features like secure boot, flash encryption, secure storage, and cryptographic accelerators.
• Compact Form Factor: The ESP32-C2 family is designed in a very compact form factor (4mm x 4mm), which is crucial for applications where space is limited or miniaturization is a concern.
• Cost-Effective Solution: These microcontrollers offer a cost-effective solution for IoT applications without compromising essential features and performance.

For now the ESP32-C2 family includes the following chips in mass production (figure ##REF:esp32c2##):

• ESP8684

(Figure 2)^[2] shows functional block diagram of ESP32-C2 chip. Main common features of the ESP32-C2 are:

Processors

• Main processor: 32-bit RISC-V single-core CPU,
  • Cores: 1 up to 120 MHz,
  • External main crystal clock
  • External 32 kHz crystal oscillator for RTC or internal RC

Wireless connectivity

• WiFi: 802.11 b/g/n (802.11n @ 2.4 GHz up to 72.2 Mbit/s) with simultaneous Infrastructure BSS Station mode/SoftApp mode/Promiscuous mode.
• Bluetooth: v5.0 Bluetooth Low Energy (BLE) ( speed: 125 Kbps - 2 Mbps) with multiple advertisement sets

Memory: Internal memory

• Embedded flash 1 , 2, 4 MiB
• ROM: 576 KiB (for booting and core functions).
• SRAM: 272 KiB (16KiB for cache).
• eFuse - 1 Kbit -256 bits reserved for encryption key and device ID

Peripheral Input/Output

• 14 x GPIO
• 3 × SPI (Serial Peripheral Interface),
• 2 x UART (universal asynchronous receiver/transmitter),
• 1 × I²C Master (Inter-Integrated Circuit),
• LED PWM up to 6 channels.
• 1 x 12-bit ADCs (analog-to-digital converter) up to 5 channels,
• General DMA controller (GDMA), with 1 transmit channels and 1 receive channels,

Power Modes

• Active Mode,
• Modem-sleep mode,
• Light-sleep mode,
• Deep-sleep mode.

Security

• Secure boot.
• Flash encryption.
• 1024-bit OTP, up to 256-bit for customers.
• Cryptographic hardware acceleration:
  • SHA1/SHA224/SHA256 (FIPS PUB 180-4),
  • ECC,
  • random number generator (RNG),
  • clock glitch filter.

For now the ESP32-C3 family includes the following chips in mass production (Table 1):

Module	Chip Embedded	Dimensions (mm)	Pins	GPIO	Flash (MB)	PSRAM (MB)	Antenna type	Development Board
ESP8684-MINI-1	ESP8684H2 ESP8684H4	13.2×16.6×2.4	53	14	1, 2, 4	N/A	PCB	ESP8684-DevKitM-1
ESP8684-MINI-1U	ESP8684H2 ESP8684H4	13.2×12.5×2.4	53	14	1, 2, 4	N/A	IPEX	ESP8684-DevKitM-1
ESP8684-WROOM-01C	ESP8684H2 ESP8684H4	24×16×3.1	22	14	2, 4	N/A	PCB	N/A
ESP8684-WROOM-02C	ESP8684H2 ESP8684H4	18x20x3.2	18	14	2, 4	N/A	PCB	N/A
ESP8684-WROOM-02UC	ESP8684H2 ESP8684H4	18x20x3.2	18	14	2, 4	N/A	IPEX	ESP8684-DevKitC-02
ESP8684-WROOM-03	ESP8684H2 ESP8684H4	15×17.3×2.8	11	8	2, 4	N/A	PCB	N/A
ESP8684-WROOM-04C	ESP8684H2 ESP8684H4	24×16×3.1	17	13	2, 4	N/A	PCB	N/A
ESP8684-WROOM-05	ESP8684H2 ESP8684H4	15×17.3×2.8	7	5	2, 4	N/A	PCB	N/A
ESP8684-WROOM-06C	ESP8684H2 ESP8684H4	15.8×20.3×2.7	21	14 or 5	2, 4	N/A	PCB	N/A
ESP8684-WROOM-07	ESP8684H2 ESP8684H4	8.5×12.7×1.9	6	3	2, 4	N/A	Solder pad for external monopole antenna	N/A

1. Note 1: When surface mounted, the module has 14 available GPIOs; when vertically soldered, the module has 5 available GPIOs.
   

Table 1: Espressif ESP32-C2 chips

The ESP32-C3 family is a series of microcontrollers developed by Espressif Systems. It's based on the RISC-V architecture and is designed to offer low-power and cost-effective solutions for various IoT (Internet of Things) applications. These chips integrate Wi-Fi connectivity, have low-power consumption, and offer various peripheral interfaces. They are suitable for diverse IoT projects, enabling developers to create connected devices efficiently. The new ESP32-C3 family is known for its compact size, low power consumption, and integration of Wi-Fi capabilities. These microcontrollers offer a balance between performance and power efficiency, making them suitable for battery-powered IoT devices. They support a variety of interfaces like SPI, I2C, UART, and ADC, enabling connectivity and interactions with various sensors and devices. This family of microcontrollers is particularly popular in smart home devices, wearables, and other IoT applications that require wireless connectivity.

The ESP32-C3 microcontrollers come with several distinctive features:

• RISC-V Core: One of the notable aspects of the ESP32-C3 family is the use of the RISC-V instruction set architecture, which provides efficiency and flexibility. This architecture allows for customization and optimization, offering a balance between performance and power consumption.
• Wi-Fi Connectivity: These chips integrate Wi-Fi connectivity, enabling devices to connect to wireless networks, making them ideal for IoT applications that require internet connectivity.
• Low Power Consumption: The ESP32-C3 family is designed with a focus on low power consumption, which is essential for battery-powered or energy-efficient IoT devices. This makes them suitable for applications where power efficiency is a priority.
• Rich Peripheral Interface Support: The microcontrollers come with a range of peripheral interfaces such as SPI, I2C, UART, PWM, and ADC. These interfaces allow easy integration with various sensors, displays, and other devices, enhancing the versatility of applications that can be developed.
• Security Features: The ESP32-C3 family includes various security features like secure boot, flash encryption, secure storage, and cryptographic accelerators. These elements contribute to the overall security of the devices developed using these microcontrollers.
• Compact Form Factor: The ESP32-C3 family is designed in a compact form factor, which is advantageous for applications where space is limited or miniaturization is a concern.
• Cost-Effective Solution: These microcontrollers offer a cost-effective solution for IoT applications without compromising essential features and performance.

For now the ESP32-C3 family includes the following chips in mass production (Table 1):

(Figure 6) shows functional block diagram of ESP32-C3 chip. Main common features of the ESP32-C3 are: ^[3]

Processors

• Main processor: 32-bit RISC-V single-core CPU,
  • Cores: 1 up to 160 MHz,
  • External main crystal clock,
  • External 32 kHz crystal oscillator for RTC or internal RC.

Wireless connectivity

• WiFi: 802.11 b/g/n (802.11n @ 2.4 GHz up to 150 Mbit/s) with simultaneous Infrastructure BSS Station mode/SoftApp mode/Promiscuous mode.
• Bluetooth: v5.0 Bluetooth Low Energy (BLE) ( speed: 125 Kbps - 2 Mbps) with multiple advertisement sets

Memory: Internal memory

• Embedded flash 4 MiB
• ROM: 384 KiB (for booting and core functions).
• SRAM: 400 KiB (16KiB for cache).
• RTC fast SRAM: 8 KiB
• eFuse - 4 Kbit - 1792 bits reserved for encryption key and device ID

Peripheral Input/Output

• 22 or 16 GPIO
• 2 x 12-bit ADCs (analog-to-digital converter) up to 6 channels,
• General DMA controller (GDMA), with 3 transmit channels and 3 receive channels,
• 1 × I²C (Inter-Integrated Circuit),
• 2 x UART (universal asynchronous receiver/transmitter),
• 1 × TWAI® controller compatible with ISO 11898-1 (CAN Specification 2.0),
• 3 × SPI (Serial Peripheral Interface),
• 1 × I²S (Integrated Inter-IC Sound),
• LED PWM up to 6 channels.
• Internal temperature sensor.
• USB Serial/JTAG controller

Security

• Secure boot.
• Flash encryption.
• 4096-bit OTP, up to 1792-bit for customers.
• Cryptographic hardware acceleration:
  • AES-128/256,
  • SHA accelerator,
  • RSA accelerator,
  • random number generator (RNG),
  • digital signature

Espressif also produces modules that are more integrative and more convenient for use by amateurs and developers. The following modules are currently available:

• ESP32-C3-Mini-1/1U^[4](Figure 7) ,
• ESP32-C3-WROOM-02/02U^[5](Figure 8).

Development kits are the most convenient for quick application or to check the capabilities of processors. They are manufactured both by Espressif itself and by many companies specializing in the production of prototype circuits. The following are some of the most versatile modules

• Espressif - ESP32-C3-DevkitM-1^[6](Figure 9),
  
• Espressif - ESP32-C3-DevkitC-02^[7](Figure 10) ,
  
• Espressif - ESP32-C3-LCDKit ^[8](Figure 11)
• Adafruit - QT Py ESP32-C3 WiFi Dev Board with STEMMA QT^[9] (Figure 12),
  
• Seeed Studio - XIAO ESP32C3 ^[10] (Figure 13),
• M5stack - M5Stamp-C3 ^[11] (Figure 14).

The Esp32-C3 as a more modern one, can successfully replace the oldest family of ESP8266 chips, so table 3 provides a brief comparison of the most important features of the ESP8266 & ESP32-S3 systems^[12]

ESP32-C6 is Espressif’s first Wi-Fi 6 SoC integrating 2.4 GHz Wi-Fi 6, Bluetooth 5.3 (Low Energy) and the 802.15.4 protocol. It is based a high-performance (HP) 32-bit RISC-V processor, which can be clocked up to 160 MHz, and also has a low-power (LP) 32-bit RISC-V processor, which can be clocked up to 20 MHz. It has a 320KB ROM, a 512KB SRAM, and works with external flash. The ESP32-C6, with its support for Wi-Fi 6 and Bluetooth 5.3, can be a potential candidate for devices seeking to integrate into the Matter standard. Matter intends to create a universal standard for smart home devices to ensure interoperability and ease of use across different brands and ecosystems. Devices equipped with the ESP32-C6, can potentially comply with the Matter standard to ensure compatibility with other Matter-certified devices and can be used to develop various other Matter-ecosystem solutions, such as Matter Gateways, Thread Border Routers or Zigbee Matter Bridges. However, the adherence to the Matter standard involves both hardware and software considerations, and manufacturers need to ensure their devices meet the required protocols for certification.

(Figure 15) shows functional block diagram of ESP32 chip. Main common features of the ESP32-C6 are: ^[13]

Processors

• Main processor: 32-bit RISC-V single-core CPU up to 160MHz,
  • Cores: 1
  • External main crystal clock
  • External 32 kHz crystal oscillator for RTC or internal RC
• Low-power processor: up to 20MHz
  • Cores: 1
  • External main crystal clock
  • External 32 kHz crystal oscillator for RTC or internal RC

Wireless connectivity

• WiFi:(802.11ax 20MHz only non-AP mode)
• WiFI:(802.11b/g/n @ 2.4 GHz up to 150 Mbit/s) with simultaneous Infrastructure BSS Station mode/SoftApp mode/Promiscuous mode.
• Bluetooth: v5.3 Bluetooth Low Energy (BLE) ( speed: 125 Kbps - 2 Mbps) with multiple advertisement sets
• IEEE 802.15.4-2015: up to 250 kbps; Thread 1.3; ZigBEE 3.0

Memory: Internal memory

• Embedded flash 4 MiB
• ROM: 320 KiB (for booting and core functions).
• HP SRAM: 510 KiB
• LP SRAM: 16 KiB
• RTC fast SRAM: 8 KiB
• eFuse - 4 Kbit - 1792 bits reserved for encryption key and device ID

Peripheral Input/Output

• 30xGPIO (QFN40) or 22xGPIO (QFN32)
• General DMA controller (GDMA), with 3 transmit channels and 3 receive channels,
• 1 × I²C (Inter-Integrated Circuit),
• 2 x UART,
• 1 x Low-Power UART,
• 2 × TWAI® controller compatible with ISO 11898-1 (CAN Specification 2.0),
• 2 × SPI (Serial Peripheral Interface for flash),
• 1 × SPI (Serial Peripheral Interface universal ),
• 1 × I²S (Integrated Inter-IC Sound),
• 1 × SDIO 2.0 slave controller
• 1 × Motor Control PWM (MCPWM)
• LED PWM up to 6 channels.
• 1 x USB Serial/JTAG controller
• 1 x Remote control peripheral (TX/RX)
• 1 x Parallel IO interface (PARLIO)
• 1 x 12-bit SAR ADCs (analog-to-digital converter) up to 7 channels,
• 1 x temperature sensor

Security

• Secure boot.
• Flash encryption.
• External Memory Encryption and Decryption (XTS_AES)
• 4096-bit OTP, up to 1792-bit for customers.
• Trusted execution environment (TEE) controller and access permission management (APM)
• Cryptographic hardware acceleration:
  • AES-128/256,
  • ECC
  • SHA accelerator,
  • RSA accelerator,
  • HASH (FIPS PUB 180-4)
  • random number generator (RNG),
  • digital signature

The following modules are currently available (Table 4):

There are not many prototype kits with ESP32-C6 SOCs on the market yet. Two sets released by the manufacturer deserve special attention. They are both entry-level development boards:

• Espressif - ESP32-C6-DevkitM-1 ^[14](Figure 18),
  
• Espressif - ESP32-C6-DevkitC-1^[15](Figure 19) .
  

They allow you to test all functions of the processor including Wi-Fi, Bluetooth LE, Zigbee, and Thread functions.