I am using the D425KT board to control external electronics through the printer port. On many boards it is possible to switch data direction by software by writing / clearing bit 5 of the control register of the parallel-port (0x378 + 2). This does not work on my D425KT however. In the BIOS I have switched the port through bidrectional, EPP and ECP, no luck. I also tried bit 6 of the control register without succes. Any suggestions?
I have finally solved the problem. Apparently the BIOS will not switch the port to bidirectional mode. Setting bit 5 in the ECP control register does however the job. To set the bit, write (decimal) 32 to the base port address + 0x402. Then the bidrectional mode works fine.