int ledPin = 13; // LED test pin
int rxPin = 0; // RX PIN
int txPin = 1; // TX TX
int byteGPS=-1;
char linea[300] = "";
char comandoGPR[7] = "$GPRMC";
int cont=0;
int bien=0;
int conta=0;
int indices[13];
void setup() {
pinMode(ledPin, OUTPUT); // Initialize LED pin
pinMode(rxPin, INPUT);
pinMode(txPin, OUTPUT);
Serial.begin(9600);
for (int i=0;i<300;i++){ // Initialize a buffer for received data
linea[i]=' ';
}
}
void loop() {
digitalWrite(ledPin, HIGH);
byteGPS=Serial.read(); // Read a byte of the serial port
if (byteGPS == -1) { // See if the port is empty yet
delay(100);
} else {
linea[conta]=byteGPS; // If there is serial port data, it is put in the buffer
conta++;
Serial.print(byteGPS, BYTE);
if (byteGPS==13){ // If the received byte is = to 13, end of transmission
digitalWrite(ledPin, LOW);
cont=0;
bien=0;
for (int i=1;i<7;i++){ // Verifies if the received command starts with $GPR
if (linea[i]==comandoGPR[i-1]){
bien++;
}
}
if(bien==6){ // If yes, continue and process the data
for (int i=0;i<300;i++){
if (linea[i]==','){ // check for the position of the "," separator
indices[cont]=i;
cont++;
}
if (linea[i]=='*'){ // ... and the "*"
indices[12]=i;
cont++;
}
}
Serial.println(""); // ... and write to the serial port
Serial.println("");
Serial.println("---------------");
for (int i=0;i<12;i++){
switch(i){
case 0 :Serial.print("Time in UTC (HhMmSs): ");break;
case 1 :Serial.print("Status (A=OK,V=KO): ");break;
case 2 :Serial.print("Latitude: ");break;
case 3 :Serial.print("Direction (N/S): ");break;
case 4 :Serial.print("Longitude: ");break;
case 5 :Serial.print("Direction (E/W): ");break;
case 6 :Serial.print("Velocity in knots: ");break;
case 7 :Serial.print("Heading in degrees: ");break;
case 8 :Serial.print("Date UTC (DdMmAa): ");break;
case 9 :Serial.print("Magnetic degrees: ");break;
case 10 :Serial.print("(E/W): ");break;
case 11 :Serial.print("Mode: ");break;
case 12 :Serial.print("Checksum: ");break;
}
for (int j=indices[i];j<(indices[i+1]-1);j++){
Serial.print(linea[j+1]);
}
Serial.println("");
}
Serial.println("---------------");
}
conta=0; // Reset the buffer
for (int i=0;i<300;i++){ //
linea[i]=' ';
}
}
}
}
看著上面的註解
還有些看不太懂
像
int byteGPS=-1;-----------------為什麼是-1
char linea[300] = "";------------linea[300]是什麼意思
char comandoGPR[7] = "$GPRMC";------------------comandoGPR[7]是什麼意思
int cont=0;
int bien=0;
int conta=0;
int indices[13];作者: coopermaa 時間: 2011-9-20 21:56
int byteGPS=-1;-----------------為什麼是-1
=> 因為 loop() 裏有一行 byteGPS=Serial.read(); 如果 serial port 沒有資料 [url=http://arduino.cc/en/Serial/Read]Serial.read()[/url] 會回傳 -1，byteGPS 為 -1 就代表沒資料，所以就把啟始值設成 -1 囉。