Datasheet

3 Functional Description
3.8.3 Watchdog Timers
ESP32-C3 contains three watchdog timers: one in each of the two timer groups (called Main System Watchdog
Timers, or MWDT) and one in the RTC module (called the RTC Watchdog Timer, or RWDT).
During the flash boot process, RWDT and the MWDT in timer group 0 (TIMG0) are enabled automatically in order
to detect and recover from booting errors.
Watchdog timers have the following features:
• four stages, each with a programmable timeout value. Each stage can be configured, enabled and
disabled separately
• interrupt, CPU reset, or core reset for MWDT upon expiry of each stage; interrupt, CPU reset, core reset, or
system reset for RWDT upon expiry of each stage
• 32-bit expiry counter
• write protection, to prevent RWDT and MWDT configuration from being altered inadvertently
• flash boot protection
If the boot process from an SPI flash does not complete within a predetermined period of time, the
watchdog will reboot the entire main system.
3.9 Cryptographic Hardware Accelerators
ESP32-C3 is equipped with hardware accelerators of general algorithms, such as AES-128/AES-256 (FIPS PUB
197), ECB/CBC/OFB/CFB/CTR (NIST SP 800-38A), SHA1/SHA224/SHA256 (FIPS PUB 180-4), and RSA3072.
The chip also supports independent arithmetic, such as Big Integer Multiplication and Big Integer Modular
Multiplication. The maximum operation length for RSA and Big Integer Modular Multiplication is 3072 bits. The
maximum factor length for Big Integer Multiplication is 1536 bits.
3.10 Physical Security Features
• Transparent external flash encryption (AES-XTS algorithm) with software inaccessible key prevents
unauthorized readout of your application code or data.
• Secure boot feature uses a hardware root of trust to ensure only signed firmware (with RSA-PSS signature)
can be booted.
• HMAC module can use a software inaccessible MAC key to generate MAC signatures for identity
verification and other purposes.
• Digital Signature module can use a software inaccessible secure key to generate RSA signatures for identity
verification.
• World Controller provides two running environments for software. All hardware and software resources are
sorted to two groups, and placed in either secure or general world. The secure world cannot be accessed
by hardware in the general world, thus establishing a security boundary.
3.11 Peripheral Pin Configurations
Espressif Systems 28
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ESP32-C3 Series Datasheet v1.2