I am building a standalone ATMega 2560 based board and I'm trying to understand the DTR / push button reset circuit.
I have copied (I believe accurately) the Arduino Mega reset circuit from the official open source schematics from the Arduino website as shown below:
The push button part of the circuit are self explanatory, RESET held high by the weak 10k pullup at R1 and pulled low when SW1 is pressed however I'm not 100% certain what C8 is doing. C8 would have charge across it after it is charged via R1. Is it just there to ensure RESET definitely goes low and remains low until charged again via R1?
The DTR side of things... again RESET is held high via R1. When DTR is pulled and held low it remains low until C8 charges again via R1. I am not sure why R2 (a fairly string pulldown) is in the circuit.
Thanks again.
I have copied (I believe accurately) the Arduino Mega reset circuit from the official open source schematics from the Arduino website as shown below:
The push button part of the circuit are self explanatory, RESET held high by the weak 10k pullup at R1 and pulled low when SW1 is pressed however I'm not 100% certain what C8 is doing. C8 would have charge across it after it is charged via R1. Is it just there to ensure RESET definitely goes low and remains low until charged again via R1?
The DTR side of things... again RESET is held high via R1. When DTR is pulled and held low it remains low until C8 charges again via R1. I am not sure why R2 (a fairly string pulldown) is in the circuit.
Thanks again.