SoPC+GPS/GSM realizes vehicle condition monitoring system

2 system software components

The system software mainly consists of the main program, the GPS management subroutine and the GSM management subroutine.

The main program completes the initialization of the system, as well as the operation management of the keyboard, LED, LCD display and car central control system.

The GPS management subroutine is primarily responsible for receiving time and location information from the GPS system.

The binary command to request the GPS system to return ASCII time position information is:

@@EqmC

Wherein, when m is 0, the response information (query) is output once, and when m is 1 to 255, the response information is output every 1~255 s (continuous);

C is the checksum (Eqm is XORed by byte);

For carriage return (hex 0d);

Wrap (hex 0a);

The command length is 8 bytes.

The response information for the command is:

@@Eq,mm,dd,yy,hh,mm,ss,dd,mm.mmmm,n,ddd,mm.mmmm,w, shhhhh.h,sss.s,hhh.h,m,t,dd. d,nn,rrrr,aa,CCC

Date: mm is the month (01~12), dd is the day (01~31), and yy is the year (99~19).

World Time (UTC): hh is the time (00~23), mm is the minute (00~59), and ss is the second (00~59).

Latitude: dd is degree (00~90), mm.mmmm is minute (00~59.9999), and n is direction (N is north and S is south).

Longitude: ddd is degree (000~180), mm.mmmm is minute (00~59.9999), w is direction (W is west, E is east).

The message length is 96 bytes.

The corresponding management subroutine is:

Int eq[8]={"@","@","E","q",1,"C",0x0d,0x0a};

Void gps_txd(int data[], int n) {

Volatile int m,sum=0;

For(m=0;m

While(~na_uart_0->np_uartstatus & 0x40);

/waiting to send ready

If(m!=n-3) {

Sum^=data[m];/calculate checksum

Na_uart_0->np_uarttxdata=data[m];/send data

}else

Na_uart_0->np_uarttxdata=sum; /send checksum

}

}

Int gps, gps_buf[46];/Define global variables

Void gps_rxd(int context) {/receive interrupt service routine

Gps_buf[gps]=na_uart_0->np_uartrxdata; /receive data

If(gps_buf[gps++]=="q") gps=0; /data positioning

If(gps>46) gps=46;/ignoring useless data

}

The GSM management subroutine is mainly responsible for data transmission and reception management of the GSM system.

The data transmission and reception of the GSM system is carried out in the form of short messages. The AT command for selecting the short message format is AT+CMGF, and the AT commands for sending and receiving short messages are AT+CMGR and AT+CMGS respectively. The corresponding management subroutine is:

Cmgf[20]={"A","T","+","C","M","G","F","=","1",0x0d};/SMS format void gsm_txd (int data[], int n) {

Volatile int m;

For(m=0;m

While(~na_uart_1->np_uartstatus & 0x40);

/waiting to send ready na_uart_1->np_uarttxdata=data[m]; /send data

}

}

Int gsm=2, gsm_buf[18]={"A","T"};

Void gsm_rxd(int context) {

/ Receive Interrupt Service Routine

Gsm_buf[gsm]=na_uart_1->np_uartrxdata; /receive data

If(gsm_buf[gsm]=="T") gsm=1;

/data positioning

If(++gsm==18) gsm=2;

}

3 Design debugging methods and design results

The actual trial results show that the SoPC-based vehicle safety monitoring system operates normally, with accurate positioning, reliable data transmission, and convenient operation and management. If equipped with GIS (Geographic Information System), the whole system will be even more powerful.