Hi,
When using the Arduinos Serial Monitor with the Arduino IDE and a Uno to just send Out basic text , if the serial monitor is closed down then opened again, it causes the program in the chip to restart from the beginning, which I gather is normal.
Using the same program code but instead connecting the serial /usb output to an independent terminal like Putty or Teraterm on the PC, it does the same thing ?
How / why do these terminal programs cause the Uno to reset when they are only receiving data ?
Is there any parameter I can change in Putty /TeraTerm to stop this happening eg I just want to occasionally view the Unos output , not monitor it all the time.
The typical serial connection has some other wires apart from the TX & Rx data, one being the DTR (opposite end to GND on a serial breakout board).
This wire gets signalled on a serial connection and on Arduino is connected to the uC RESET.
On UNO, things are not exactly as above since there is a 2nd ATMega used for the serial, but the principle is the same.
Looking at
Sparkfun Uno R3 board, there is a 'RESET EN' jumper which is shorted by a trace and allows the reset to happen.
You can - using a knife - cut through the track between the jumper breaking it, then solder/un-solder it when required or not.
Note though that when flashing from the IDE, the board must be reset somehow, so having the jumper disconnected will require
the user to reboot it by pressing the reset button on the board at the appropriate time - so really not ideal!
Could do with a proper pinheader jumper fitted ....
I have yet to see any setting that stops the sending of the DTR signal from the host side, but there may be one
I'm guessing it's probably something to do with the driver rather than the serial terminal being used
You can ofcourse get another serial breakout board and then connect its Rx (plus a Gnd) to the boards Tx (D1) header so you can then see the serial output.
Opening/connecting/closing this won't cause any resets