March 30, 2023, 11:59:39 pm

ESP32-C3 and ULP

Started by timokett81, December 30, 2022, 07:47:20 am

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Does anyone know if the ESP32-C3 has the ULP-RISC-V co-processor?
The technical reference manual mentions ULP only briefly in topics and The spec has has "Preliminary" water stamps so this may be just copy-paste from other specs. The ESP32-C3 API does not mention ULP at all.
The ESP32-S3 technical reference has whole topic for ULP.

I have used ESP32-S2 ULP successfully in low power measurements so I would be interested on this too if it has an ULP.


You'd better post this question in the espressif forums. They'd know better about their chip.

From what we know the ESP32-C3 chip low-power modes are called: light-sleep mode, and deep-sleep mode.

In light-sleep mode, the digital peripherals, most of the RAM, and CPUs are clock-gated and their supply voltage is reduced. Upon exit from light-sleep, the digital peripherals, RAM, and CPUs resume operation and their internal states are preserved.

In deep-sleep mode, the CPUs, most of the RAM, and all digital peripherals that are clocked from APB_CLK are powered off. The only parts of the chip that remain powered on are:

RTC controller

RTC fast memory

Technical support and documentation manager at Olimex


I found out that ESP32-C3 does not have ULP. They will remove the ULP parts from technical reference, some day.
RISC-V ULP is supported in ESP32-Sx series.