Advise: Please read Quectel_BC26-OpenCPU_User_Guide_V10 in /doc ;
this project may not be perfect in function, just a demo; It can connect to MQTT server ,subscribe topic ,publish or recieve messages in 0/1/2 qos;

make and download

OPEN BC26_OpenCPU_NB1_SDK_V1.3/MS-DOS
use make clean to clean existing OBJ files;
use make new to make APP file ,then use Qflash tool download APP file via serrial port; APP.C in ./BC26_OpenCPU_NB1_SDK_V1.3/custom/ contains the main_task . start from here;

note: make sure your module is BC26NBR01A07 or update this or newly factory file with Qflash tool first

please refer to line 115 in APP.c replace the ~~~ mark with your own paras

MQTT_Para_t MQTT_para = {0, 0, 0, 0, 0, 0, NULL, NULL, NULL, NULL, NULL};
char SERVER_ADDR[] = "" ~~~ "\0" ;
char CLIENT_ADDR[] = "" ~~~ "\0" ;
char USERNAME_ADDR[] = "" ~~~ "\0" ;
char PASSWD_ADDR[] = "" ~~~ "\0" ;
char TOPIC_ADDR[] = "" ~~~ "\0" ;
char testpayload[] = "" ~~~ "";