Espressif ESP32-S2 User Manual

Chapter 4. API Guides
(continued from previous page)
# version: ">=2.0.0"
#
# # For transient dependencies `public` flag can be set.
# # `public` flag doesn't affect the `main` component.
# # All dependencies of `main` are public by default.
# public: true
#
# # For components hosted on non-default registry:
# service_url: "https://componentregistry.company.com"
#
# # For components in git repository:
# test_component:
# path: test_component
# git: ssh://git@gitlab.com/user/components.git
#
# # For test projects during component development
# # components can be used from a local directory
# # with relative or absolute path
# some_local_component:
# path: ../../projects/component
4.28 ULP Coprocessor programming
4.28.1 ESP32-S2 ULP coprocessor instruction set
This document provides details about the instructions used by ESP32-S2 ULP coprocessor assembler.
ULP coprocessor has 4 16-bit general purpose registers, labeled R0, R1, R2, R3. It also has an 8-bit counter register
(stage_cnt) which can be used to implement loops. Stage count regiter is accessed using special instructions.
ULP coprocessor can access 8k bytes of RTC_SLOW_MEM memory region. Memory is addressed in 32-bit word
units. It can also access peripheral registers in RTC_CNTL, RTC_IO, and SENS peripherals.
All instructions are 32-bit. Jump instructions, ALU instructions, peripheral register and memory access instructions
are executed in 1 cycle. Instructions which work with peripherals (TSENS, ADC, I2C) take variable number of
cycles, depending on peripheral operation.
The instruction syntax is case insensitive. Upper and lower case letters can be used and intermixed arbitrarily. This
is true both for register names and instruction names.
Note about addressing
ESP32-S2 ULP coprocessor’s JUMP, ST, LD instructions which take register as an argument (jump address,
store/load base address) expect the argument to be expressed in 32-bit words.
Consider the following example program:
entry:
NOP
NOP
NOP
NOP
loop:
MOVE R1, loop
JUMP R1
When this program is assembled and linked, address of label loop will be equal to 16 (expressed in bytes). However
JUMP instruction expects the address stored in register to be expressed in 32-bit words. To account for this common
Espressif Systems 1476
Submit Document Feedback
Release v4.4

Espressif ESP32-S2 Specifications

General

Brand	Espressif
Model	ESP32-S2
Category	Single board computers
Language	English