10f99eeccSopenharmony_ci# IoT Hardware<a name="EN-US_TOPIC_0000001117425053"></a> 20f99eeccSopenharmony_ci 30f99eeccSopenharmony_ci- [Introduction](#section11660541593) 40f99eeccSopenharmony_ci- [Directory Structure](#section1464106163817) 50f99eeccSopenharmony_ci- [Constraints](#section1718733212019) 60f99eeccSopenharmony_ci 70f99eeccSopenharmony_ci## Introduction<a name="section11660541593"></a> 80f99eeccSopenharmony_ci 90f99eeccSopenharmony_ciThe Internet of Things \(IoT\) hardware subsystem provides APIs for operating IoT devices, including flash, general-purpose input/output \(GPIO\), Inter-Integrated Circuit \(I2C\), pulse width modulation \(PWM\), universal asynchronous receiver-transmitter \(UART\), and watchdog APIs. 100f99eeccSopenharmony_ci 110f99eeccSopenharmony_ci## Directory Structure<a name="section1464106163817"></a> 120f99eeccSopenharmony_ci 130f99eeccSopenharmony_ci``` 140f99eeccSopenharmony_ci/base/iothardware/peripheral 150f99eeccSopenharmony_ci├── interfaces 160f99eeccSopenharmony_ci └── inner_api # APIs for operating IoT devices 170f99eeccSopenharmony_ci``` 180f99eeccSopenharmony_ci 190f99eeccSopenharmony_ci## Constraints<a name="section1718733212019"></a> 200f99eeccSopenharmony_ci 210f99eeccSopenharmony_ciThe IoT hardware subsystem is compiled using the C language. Currently, only the Hi3861 development board is supported. If you want to use other chips, you need to implement OpenHarmony APIs. 220f99eeccSopenharmony_ci 23