esp-idf/components/soc/README.md

soc

The soc component provides hardware description for targets supported by ESP-IDF.

- `xxx_reg.h`   - defines registers related to the hardware
- `xxx_struct.h` - hardware description in C `struct`
- `xxx_channel.h` - definitions for hardware with multiple channels
- `xxx_caps.h`  - features/capabilities of the hardware
- `xxx_pins.h`  - pin definitions
- `xxx_periph.h/*.c`  - includes all headers related to a peripheral; declaration and definition of IO mapping for that hardware