I'm trying to output some data thru the parallel port.
But i can only output using the DATA ports and not the CONTROL ports..
Do i need to initialise the CONTROL ports before i can as them as output?

I'm using the command 'outportb'.

Thanks.

Don't forget that there's one input control control address (nominally
at 0x379) and one output control address (nominally at 0x37a) for a
standard parallel port with data output at address 0x378.

While it shouldn't affect you, remember that for machines that have
bidirectional ports (whether configured as an ECP, EPP or SPP),
setting bit 5 of 0x37a will switch off the output drivers at address
0x378.

Cheers
Glenn

i try sending continuous '0's and '1' throught the data port(0x3BC). Using a oscillascope, i can see a square wave. But i try doing that to the control port(0x3BE), i can only see a high output.

Or is there any other way in which i can test these ports?

I presume you know the pin assignments on the parallel port and how
they relate to the various PC I/O addresses:

DB25 pin allocation
        data outputs    port_in         port_control
bit 0      pin 2                                pin 1 (inverted)
bit 1   pin 3                           pin 14 (inverted)
bit 2   pin 4                           pin 16
bit 3   pin 5           pin 15          pin 17 (inverted)
bit 4   pin 6           pin 13
bit 5    pin 7          pin 12
bit 6   pin 8           pin 10
bit 7   pin 9           pin 11 (inverted)

Addresses: port_in = data output address + 1
        port_control = data output address + 2

Cheers
Glenn