Yp-05 Schematic !!top!! -

Standard 6-pin header including DTR, RXD, TXD, VCC, CTS, and GND .

The DTR pin on the YP-05 is essential here, as it triggers the necessary hardware reset that allows the bootloader to accept new code. Yp-05 Schematic

Data Terminal Ready; used to auto-reset microcontrollers (like Arduino) for programming. Standard 6-pin header including DTR, RXD, TXD, VCC,