esp-idf/components/soc/README.md

The SoC component

The soc component provides register-level descriptions for targets supported by ESP-IDF.

File	Description
xxx_reg.h/xx_struct.h	Defines registers layout of a specific module. These files are automated, and should not be updated manually. Please note the register names and layout are subject to change between different chip series.
xxx_pins.h	Defines the unchangeable GPIOs used by a specific module. e.g. if a high speed signal is routed through IO MUX, its corresponding GPIO is not selectable.
soc_caps.h	Describes the differences in capabilities between different chips. The macros here can also affect cmake build system, Kconfig system, docs system, pytest and CI environment. Changes to this file requires extra caution as they are part of the public API.
xxx_periph.h	This is the portal for each peripheral module at the SoC layer, containing all relevant register header files and organizing other key information, such as interrupt sources, hardware signal IDs, etc.
xxx.peripherals.ld	This is the linker script that defines each module's memory address.

The SoC Capabilities

There are two documents describing SoC capabilities, soc_caps.h and soc_caps_full.h. The former is a public header file, and the information in it is coarse-grained. The latter is a header file for internal developers that contains fine-grained module information. To used the soc capability macros, you should use the macro functions offered by soc/soc_caps_eval.h.

Macro function	Description	Example
SOC_IS	Checks if the current SoC is a specific one.	SOC_IS(ESP32)
SOC_HAS	Checks if the current SoC has a specific module.	SOC_HAS(DAC)
SOC_MODULE_ATTR	Get the attribute of a specific module.	SOC_MODULE_ATTR(GPTIMER, TIMERS_TOTAL)
SOC_MODULE_SUPPORT	Checks if the current SoC supports a specific feature.	SOC_MODULE_SUPPORT(GPTIMER, ETM)