Hi all,
I am trying to workout connection with SIM900 using Arduino Nano software serial on pins rx(2) tx(3).
Situation is frustrating because of the matter that all works except one thing and that is Nano to SIM900.
Situation is exactly the same as in the picture included ( I've made it 8)
So there is:
- Arduino Nano
- DB9 MAX232 module
- PL2303 USB to SERIAL
- SIM900 module
- Of course my laptop (not on the picture
All connections are 9600-8-N-1 no flow control
Situation1:
Laptop is connected to pl2303 and then to SIM900.
I can issue AT commands , send messages all works fine.
I've connected SIM900 TX,RX,GND to pl2303 pins 2,3,5.
Software putty
Situation2:
Laptop is connected to Arduino Nano Software serial on pins 2,3.
Laptop can receive messages from Arduino Nano, also Nano reads serial data and shows that on Serial console.
I've connected Arduino Nano with pins 2,3 to DB MAX232 pins labeled RX,TX (2-RX, 3-TX), then to pl2303.
#include <SoftwareSerial.h>
SoftwareSerial mySerial(2, 3); // RX, TX
void setup() {
Serial.begin(9600);
mySerial.begin(9600);
Serial.println("--->");
}
void loop() {
if(mySerial.available()>0){
Serial.println("Data available");
char c = mySerial.read();
Serial.write(c);
}
}
Situation3:
Arduino is connected to SIM900 over DB9 MAX232 module on software serial pins 2,3.
#include <SoftwareSerial.h>
SoftwareSerial mySerial(2, 3); // RX, TX
void setup() {
Serial.begin(9600);
mySerial.begin(9600);
Serial.println("--->");
mySerial.print("AT\r\n");
delay(1000);
}
void loop() {
if(mySerial.available()>0){
Serial.println("Data available");
char c = mySerial.read();
Serial.write(c);
}
}
Nothing happens. Data available never shows up.
I tried to exchange pins mySerial(2, 3) to mySerial(3, 2) still nothing.
After trying I always reconnect to pl2303 to verify that all connections are good.
All is done with DB9 connectors so there is no issue of reconnection and missing wire connections.
Any help or hint would be greatly appreciated!
Tnx for helping out.
