Some question for nano schematic

Other Hardware General Electronics
1

HI ALL

I have a question for nano schematic.

There's a capacitance series connect on FT232RL Pin 2(DTR#)

i don't understand the use of that capacitor , in the link there's a Sign for C4 is what i'm asking for .

why need to connect capacitor instead of connecting directly?

thanks all . :o

2

Because the reset needs only a pulse to begin the reset, not a level for an extended period of time.

Paul

3

superme55557:
HI ALL

I'm have a question for nano schematic.

There's a capacitance series connect on FT232RL Pin 2(DTR#)

i don't understand the use of that capacitor , in the link there's a Sign for C4 is what i'm asking for .

why need to connect capacitor instead of connecting directly?

thanks all . :o

https://www.arduino.cc/en/uploads/Main/Arduino_Nano-Rev3.2-SCH.pdf

resetC4.jpg
resetC4.jpg939×450 69.7 KB

C4 is in series between the reset switch and the 232RL DTR# pin.
This is so when the reset is pushed a "short" pulse goes the the DTR#.
The DTR# pin has to be left open circuit when the IC is being used, but needs a pulse to do its own reset/load process.
C4 prevents any DC, 0V or 5V from being externally applied to DTR#.

Hope that's right.. Tom.. :slight_smile:
PS. I really hate "SearchAWord" schematics.