• PD0 (pin 16): digital I/O pin
• PD1 (pin 15): digital I/O pin
• PD2 (pin 14): digital I/O pin
• PD3 (pin 13): digital I/O pin
• PD4 (pin 12): digital I/O pin
• PD5 (pin 11): digital I/O pin
• PD6 (pin 10): digital I/O pin
• PD7 (pin 9): digital I/O pin

thank you, ChatGPT

• In Circuit Programming
  • for some reason the chip ran at 1/2 speed when doing this but the same chip ran at normal (32MHz) speed when using the bootloader. No fuses (that I know of) were changed. (???)
• low power mode with the arduino framework