slide 6 of 14

Using Parallel Ports

• Each parallel port has 3 I/O registers
  • 8 bit data output (sometimes bidirectional)
  • 5 bit status input
  • 4 bit (supposedly) open-collector control output
• SPP, bidirectional, ECP, and EPP
  http://www.lvr.com/parport.htm
• Typically I/O mapped, ~1-2 microseconds
• Parallel port cards as low as $8