I have two questions that I was hoping someone could clarify with a quick True/False. When using the ATtiny85/85/2313 the reset pin is connected to a 10k resistor which is connected to VCC.

  1. When programming with an AVR 6 pin programmer does the reset pin on an ATtiny at that point need to be connected to the 10k resistor to VCC?

  2. When using an Arduino Uno to program an ATtiny, the reset pin on the attiny is connected to D10. Does the reset pin additionally also need to be connected to a 10k resistor to VCC?

Or to summarize does the reset pin on an ATtiny84/85/2313 always need to be connected to a 10k resistor to VCC?


Yes, always connect the Reset Pin of the ATtiny to VCC through a 10k resistor. It can't hurt, and it can help (prevent your device from resetting randomly).


To prevent spurious resets, it is good practice to connect a controller's reset pin through a 10k resistor to V(CC). However while connected to the programmer a 10k resistor won't hurt, but it is not really necessary. The programmer will use one of its low impedance output pins to pull the controller's pin to the desired level (up or down). In that case the 10k resistor has no effect at all because the programmer's output has much lower impedence.

Notice though that once the programmer finishes programming the device, it is unknown to me what will happen to the programmer's outputs (and with that the logic level on the controller's reset pin). If the programmer turns it pins to high impedance / input state, then the 10k resistor on the controller's reset is advisable again.

Of course the 10k resistor is unnecessary when the reset pin is attached to a logic output from another chip.

In other words: The 10k resistor on reset to V(CC) doesn't hurt while programming, but it prevents unintended resets once done.


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