Hi, I want to design atmega328p (referenced data source: https://www.apogeeweb.net/circuitry/atmega328p-microcontroller-datasheet-pinout-circuit.html) on PCB... One method to upload code is using Arduino Uno. If I disconnect the wires from arduino uno side but left them in atmega328p side, will be there any problem such as open circuit because of wires? My idea is to solder the wires in PCB and when I need to upload code or monitor data I connect these wires to arduino uno. Is there anyone have ideas of it?
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Lernend B. wrote: > uno side but left them in atmega328p side, will be there any problem > such as open circuit because of wires No, but your ATmega328 needs to be preprogrammed with the Arduino bootloader, so either pulled off an arduino board or programmed with the bootloader code using some other method, like the native MISO, MOSI, SCLK, RESET Interface. And if you can program an ATmega328 using this method, why not use it for the real program and skip the Arduino completley.
Open wires have an impact if you use the same I/O pins for other communication, e.g. a display with SPI interface. It depends on the length of wires and the amount of radio waves in the area. For development phase on the desktop this is usually no problem, specially if the wires are as short as 30cm .
The I²C is much more affected because is has weaker pull-up resistors compared to the active HIGH level driven by I/O pins. But even I²C does usually work fine with short open wires.
ISPC - In Circuit Serial Programming is meant for exactly that. Arduinos for example are build that way, these connections stay after programming.