ATtiny85 - Initial LED on example for post

main.c

// Port B data direction register 0x17 (+ 0x20 for the special func register offset)
#define DDRB *((volatile unsigned char*)0x37)

// Port B data register 0x18 (+ 0x20 for the special func register offset)
#define PORTB *((volatile unsigned char*)0x38)

int main()
{
  // Set data direction for Port B bit 0 (PB0 - pin 5)
  DDRB |= (1 << 0);

  // Set data for Port B bit 0 (PB0 - pin 5) to 1
  PORTB |= (1 << 0);
  
  while (1) {}
}