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[on:]

Hello friends.

I'm trying to talk with an Arduino through another unchipped arduino.

The code is:

void setup() {
  Serial.begin(9600);
  pinMode(2, INPUT);
}

void loop() {
  Serial.println("send");

  if (Serial.available()) {
    Serial.read();
  delay(500);
    Serial.println("OK");
  }
  delay(500);
}

When I connect with de chipped arduino directly with usb I get "send" every 1/2 seconds and "OK" every time I send something. PERFECT
If I connect using the unchipped arduino (gnd->gnd, vin->vin, tx->tx, rx->rx) I get "send" every 1/2 seconds and "OK" only some times. 1 every 20 times or less. It's... aleatory.

Any idea?

Thanks

[Reply #1 on:]

Hello friends.

Now I'm getting correct answer if I get Rx signal directly from pin 1 of FTDI.

PC <-> USB <->Arduino w/o atmega <-> ftdi pin 1 <-> Chipped board rx pin
                                     tx pin     <-> Chipped board tx pin
                                     5v         <-> 5v
                                     gnd        <->  gnd

Why is this happening?

[Reply #2 on:]

Why is this happening?

Because you now have the hardware connected correctly.

[Reply #3 on:]

mnnn... but if I use arduino pin 0 instead of use ftdi pin 1, I can't get correct transmission.

Why can't I use tx and rx pins directly?

PD: Now I'm using a transmission based on Messenger library.

[Reply #4 on:]

The connection from the "Arduino pin 1" to the FTDI pin is through the chip that you removed.

[Reply #5 on:]

¿?
http://arduino.cc/it/uploads/Main/arduino-duemilanove-schematic.pdf

FTDI txd goes to R8 first, atmega pin 2 and j1 pin 0 later.

Am I wrong?

In my test, I can get signal from one side of R8 (ftdi side) but not from the other side.

I have used different arduinos with same result.