For MCUs that have no network communication capabilities, the "MCU + communication module" combination is often used. Communication modules (including Wi-Fi/2G/4G/NB-IoT) generally provide serial port-based AT instruction protocols for MCUs to communicate over the network. For this scenario, the C-SDK encapsulates the AT-socket network layer, where the core protocol and service layer don't need to be ported. This document describes how to port C-SDK for connection to IoT Hub in the target environment of MCU (FreeRTOS) + universal TCP AT module.
Download the latest version of the device C-SDK.
Use the general TCP module to compile and configure the options as follows:
Name | Configuration | Description |
---|---|---|
BUILD_TYPE | debug/release | Set as needed |
EXTRACT_SRC | ON | Enable code extraction |
COMPILE_TOOLS | gcc/MSVC | Set as needed and ignore in case of IDE |
PLATFORM | Linux/Windows | Set as needed and ignore in case of IDE |
FEATURE_OTA_COMM_ENABLED | ON/OFF | Set as needed |
FEATURE_AUTH_MODE | KEY | Key authentication is recommended for resource-constrained devices |
FEATURE_AUTH_WITH_NOTLS | ON/OFF | Enable TLS as needed |
FEATURE_EVENT_POST_ENABLED | ON/OFF | Enable event reporting as needed |
FEATURE_AT_TCP_ENABLED | ON | Whether to enable TCP feature in AT module |
FEATURE_AT_UART_RECV_IRQ | ON | Whether to enable receipt interruption feature in AT module |
FEATURE_AT_OS_USED | ON | Whether to enable multithreaded feature in AT module |
FEATURE_AT_DEBUG | OFF | The AT module debugging feature is disabled by default, and it needs to be enabled during debugging |
Run the following command on Linux:
mkdir build
cd build
cmake ..
You can find the relevant code files in output/qcloud_iot_c_sdk
with the following directory hierarchy:
qcloud_iot_c_sdk
├── include
│ ├── config.h
│ ├── exports
├── platform
└── sdk_src
└── internal_inc
Note:
include
directory: contains the SDK APIs and variable parameters, whereconfig.h
is the compilation macros generated according to the compilation options.platform
directory: contains platform-related code, which can be modified and adapted according to the specific conditions of the device.sdk_src
directory: contains the SDK core logic and protocol-related code, which generally don't need to be modified, whereinternal_inc
is the header file used internally by the SDK.
- You can copy
qcloud_iot_c_sdk
to the compilation and development environment of your target platform and then modify the compilation options as needed.
Please refer to Overview to port first.
For network HAL APIs, the AT_Socket
framework provided by the SDK has been selected through the above compilation options. The SDK will call the at_socket
API of network_at_tcp.c
. You don't need to port the at_socket
layer, but you need to implement the AT serial port driver and AT module driver. For the AT module driver, you only need to implement the driver API of the driver structure at_device_op_t
in at_device
of the AT framework. You can refer to the supported modules in the at_device
directory.
Currently, the SDK provides underlying API implementation for the Wi-Fi module ESP8266, which is widely used in the IoT field, for reference when you port to other communication modules.
You can refer to the routines in the SDK's samples
directory for development.
Was this page helpful?