Dear All
I build RS232 level shifter using max232, and use it wih NewSoftSerial at pin 4,5
My arduino is Arduino 2009
And here is my test script
#include <NewSoftSerial.h> //Include library newsoftserial
#include <string.h>
char incoming_char=0; //incoming char
char incoming_char_buff[300] ; //Incoming char buffer
int incoming_char_idx = -1 ; // Incoming char index
NewSoftSerial cell(4,5);
bool isprintline = 1;
void setup(){
Serial.begin(19200);
cell.begin(4800);
delay(2000);
Serial.println("Get Ready");
delay(2000);
}
long myint = 0 ;
void loop(){
/*
cell.print("This is line number : ");
cell.println(myint);
Serial.print("This is line number : ");
Serial.println(myint);
myint++;
delay(1000);
*/
myint++;
Serial.print("Loop Number : ");
cell.print("Loop Number : ");
Serial.println(myint);
cell.println(myint);
Serial.println("Let's check all lines");
Serial.println("Check Cell Line");
if(cell.available() >0){
do_cell();
}
Serial.println("Check Serial Line");
if(Serial.available() >0){
do_ser();
}
delay(1000);
if (isprintline){
Serial.print("-----NO Thing Happen----------");
cell.print("-----NO Thing Happen----------");
}
isprintline = 1 ;
}
void do_cell(){
Serial.println("Reading Cell line");
delay(100);
incoming_char_idx=-1;
while (cell.available()){
incoming_char_idx++ ;
incoming_char=cell.read();
incoming_char_buff[incoming_char_idx]=incoming_char ;
}
if ( incoming_char_idx > -1){
incoming_char_idx++;
incoming_char_buff[incoming_char_idx]='\0';
Serial.print("Cell Said : ");
Serial.println(incoming_char_buff);
}
cell.flush();
isprintline = 0 ;
}
void do_ser(){
Serial.println("Reading Serial line");
delay(100);
incoming_char_idx= -1;
while (Serial.available()){
incoming_char_idx++ ;
incoming_char=Serial.read();
incoming_char_buff[incoming_char_idx]=incoming_char ;
}
if ( incoming_char_idx > -1){
incoming_char_idx++;
incoming_char_buff[incoming_char_idx]='\0';
Serial.print("You type : ");
Serial.println(incoming_char_buff);
cell.println(incoming_char_buff);
delay(1000);
}
isprintline = 0 ;
}
- First, I test it to connect to my other PC via it’s Com Port, and the result is :
a. When at the PC side I do not do monitor (i.e cat /dev/ttyS0) , the script output (at serial monitor window) just fine.
I can send text from PC to arduino and vise versa.
Arduino only detect any input on NewSoftSerial pin only if PC send text
b. When I do monitoring at PC side using → cat /dev/ttyS0 … the script output (at serial monitor window) start showing a “garbage”
Arduino always see there is “something” on NewSoftSerial pin …
- Second … I change NewSoftSerial speed to 4800 , and attached my GPS (using cross cable), and the result is : Arduino start getting “garbage”.
Attached is screen capture of my serial_monitor when GPS attached.
Kindly please give me your enlightment on how to fix it.
Sincerely
-bino-
