Chapter 2. API Reference
void esp_rom_install_uart_printf(void)
Install UART1 as the default console channel, equivalent to esp_rom_install_channel_putc(1,
esp_rom_uart_putc)
soc_reset_reason_t esp_rom_get_reset_reason(int cpu_no)
Get reset reason of CPU.
Return Reset reason code (see in soc/reset_reasons.h)
Parameters
• cpu_no: CPU number
Code examples for this API section are provided in the system directory of ESP-IDF examples.
2.7 API Conventions
This document describes conventions and assumptions common to ESP-IDF Application Programming Interfaces
(APIs).
ESP-IDF provides several kinds of programming interfaces:
• C functions, structures, enums, type definitions and preprocessor macros declared in public header files of ESP-
IDF components. Various pages in the API Reference section of the programming guide contain descriptions
of these functions, structures and types.
• Build system functions, predefined variables and options. These are documented in the build system guide.
• Kconfig options can can be used in code and in the build system (CMakeLists.txt) files.
• Host tools and their command line parameters are also part of ESP-IDF interface.
ESP-IDF consists of components written specifically for ESP-IDF as well as third-party libraries. In some cases, an
ESP-IDF-specific wrapper is added to the third-party library, providing an interface that is either simpler or better
integrated with the rest of ESP-IDF facilities. In other cases, the original API of the third-party library is presented
to the application developers.
Following sections explain some of the aspects of ESP-IDF APIs and their usage.
2.7.1 Error handling
Most ESP-IDF APIs return error codes defined with esp_err_t type. See Error Handling section for more infor-
mation about error handling approaches. Error Code Reference contains the list of error codes returned by ESP-IDF
components.
2.7.2 Configuration structures
Important: Correct initialization of configuration structures is an important part in making the application com-
patible with future versions of ESP-IDF.
Most initialization or configuration functions in ESP-IDF take as an argument a pointer to a configuration structure.
For example:
const esp_timer_create_args_t my_timer_args = {
.callback = &my_timer_callback,
.arg = callback_arg,
.name = "my_timer"
};
esp_timer_handle_t my_timer;
esp_err_t err = esp_timer_create(&my_timer_args, &my_timer);
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