I'm designing a PCB with a standard arduino ATMEGA328 DIP IC. Do I need to make a connection to the reset pin?
asked Jun 12, 2015 at 15:35
-
You absolutely need one! What if you have to reset your processor but you can't detach from the power supply?Stefa168– Stefa1682015年06月12日 17:26:29 +00:00Commented Jun 12, 2015 at 17:26
2 Answers 2
"Atmel AVR042: AVR Hardware Design Considerations"
AVR reset connections
answered Jun 12, 2015 at 15:42
-
+1 for the ref. "The reset line has an internal pull-up resistor, but if the environment is noisy it can be insufficient and reset can therefore occur sporadically." So it seems one could possibly live without in "quiet" environments...Edgar Bonet– Edgar Bonet2015年06月12日 15:52:56 +00:00Commented Jun 12, 2015 at 15:52
-
2Certainly. None of my prototypes use the above circuit, but my final products do.Ignacio Vazquez-Abrams– Ignacio Vazquez-Abrams2015年06月12日 15:58:37 +00:00Commented Jun 12, 2015 at 15:58
-
I don't get the diode however, if you only connect a button. Can noise really cause it to enter high-voltage-programming-mode?Gerben– Gerben2015年06月13日 12:53:34 +00:00Commented Jun 13, 2015 at 12:53
Yes, you do. The pin needs to be pulled up to Vcc via a pullup resistor - typically 10KΩ. Also, if you are using the Arduino bootloader and want to program via serial then this pin should be connected to your serial interface's DTR pin through a 100nF (typically) capacitor. It is also often desirable to provide a reset button which switches this pin to ground.
You should examine the Arduino Uno's schematics and use them as a reference.
answered Jun 12, 2015 at 15:41