How do I program the AT-MIO16E-10 digital IO from dos once I have established the IO_Base Address

[rpires]

I have established an IO base address of 0x240 for the card, but I don't understand the sequence of

control operations on how to toggle discrete lines on port A, B or C on the 82c55a chip. The register-level

manual gives offset of port A, B, C and a Control register for the ATMIO16-E-10 and have tried the

following:  

ControlReg   = 0x1f

BaseAddr      = 0x240

PortA offset   = 0x19

outp( BaseAddr + ControlReg, 0x80 )     /// make all ports output

outp ( BaseAddr + PortA, 0 )

Any help would be appreciated!!!

Thanks