"It’s important though, that we don’t hold the 328P in reset. We just want to pulse the pin very, very briefly, so that the bootloader can listen to SERIAL_Rx and determine if a new sketch is being sent. When the RESET pin on the 328P is low, all the pins (except for the ICSP pins, I believe) are set to a high impedance state, effectively killing the serial pins. So we pulse the Pin 1 on the 328P to issue the reset, not drag it low then drag it high again."
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