51 MCU controls SIM300 to send and receive data

rissun

51 MCU controls SIM300 to send and receive data [Copy link]

Dear experts, I want to use 51 to control SIM300 to send and receive data through the serial port. Now I have connected the SIM300 module and 51 experimental board through the serial port, but the module does not respond after writing the program. I don't know why. Do I need to initialize the module? I posted the program here to trouble you to see if there is any problem. In addition, I want to use the serial port to receive a string and determine whether the received string is the one I want. How can I do it? I have tried several methods but none of them worked. #include
#define unchar unsigned char #define unint unsigned int unchar *re; void chushihua() { TMOD=0x20; TH1=0xfd; TL1=0xfd; TR1=1; SM0=0; SM1=1; REN=1; EA=1; ES=1; PCON=0x00; } void send_byte(unchar c) { SBUF=c; while(TI!=1); TI=0; } void send_string(unchar *str) { while(*str!='\0') { send_byte(*str++); } } chuli() { if(re=="error")//Judge whether the received string is "error" (I don't know if this is the right way to do it)——! { send_string("ATD4302099"); send_byte(0x0d); } } main() { chushihua(); send_string("ATD4302099"); delay(); send_byte(0x0d); chuli(); } void reveive() interrupt 4 { if(RI) { *re=SBUF; re++; RI=0; } }

shen2089

Let me tell you a good method: go to the Internet to download a serial port debugging assistant, and you can see at a glance what you sent and what you received~~

heys

I have used this software, sending and receiving are normal, but the module just doesn’t respond, I am so depressed. . . . .

天天

As long as the baud rate is set correctly and the serial port is open, there should be no problem. You can send the two characters AT. Of course, don't forget to add the carriage return after it, that is, \r~~~ If successful, it will return ok. If not, it depends on whether your hardware has a problem.

petrified

This is not wireless, right?

batonsoft

The RTS line of SIM300 Serial port 1 is not pulled low, or use Serial port 2. Port 1 is a seven-wire system, and port 2 is a two-wire system.

fengleichen

After booting, wait until Call Ready appears before sending the ATD command. It is best to use the serial port assistant to debug the module first, and then write the program, which will save debugging time.

junweisteven

It seems that you initialize the pin