PCI-6503 configuration - split port C

Question

Quite a few years ago I wrote a program that used a DIO-24 to read and write data from a test fixtrue with FIFOs and other junk on it. I could not find a clean way to configre the 8255  in mode 0 with ports A, B, and C_lo_nibble as inputs and C_hi_nibble as output with any of the supplied NI code.
At the time the solution was to use WriteToPhysicalMemory and ReadFromPhysicalMemory as below:
// configure 8255
    Get_DAQ_Device_Info (1, ND_BASE_ADDRESS, &dio24_base);
    dio24_portA=dio24_base;
    dio24_portB=dio24_base+1;
    dio24_portC=dio24_base+2;
    dio24_control=dio24_base+3;
    sb[0]=0x093;    WriteToPhysicalMemory ( dio24_control, sb, 1);
Over the years newer similar projects switched to PCI-6503s and all worked fine until a NI security patch removed support for WriteToPhysicalMemory and ReadFromPhysicalMemory and other direct memory access.
See:
<http://digital.ni.com/public.nsf/allkb/A07451671E7263598625792800677970>
The simple DIG_Prt_Config does not seem to support split input/output on the 8255's port C.
Can anyone point me in a relatively simple method of regaining split I/O on port C of the 6503?
Thanks in advance,
Ed Yoho

Answer 1

Emily,
The initial refererenced document (Digital I/O Applications) uses the outp() function and then "ors" the required configuration bits to create an eight bit word with the binary value of 10010011 for split port C operation.
The line:
outp(dio24_control, 0x093);
is the configuration statement and is sending an eight bit word with 10010011 in it (Mode 0 Number 11) to the address. as found by:
    Get_DAQ_Device_Info (1, ND_BASE_ADDRESS, &dio24_base);
The problem is "outp()" was designed way back at the beginning of the PC world (8086 / EGA days) and was limited to addresses from 0 through 03FF (or maybe 03F0, I can't remember for sure).
If the module was an ISA based device, this would still work. When using a PCI interfaced device, the module address is well outside the area defined above.
If you look at B-11 "PCI Initialization for the PC", you will be a bit closer. This is close to what I did when switching from the old ISA DIO-24 (that used outp() and inp() functions) to the PCI-6503.
When switching from ISA to PCI quite a few years ago, I discovered the built in configuration functions within Labwindows still did not seem to support splitting port C on 8255s. That is when I started using the WriteToPhysicalMemory and ReadFromPhysicalMemory as direct register write/read.
Unfortunately, National has removed WriteToPhysicalMemory and ReadFromPhysicalMemory and now I am stuck looking for a replacement.
What I am looking for / in need of is a replacement for the two deleted functions that will allow me to directly read/write the 8255. Unfortunately, outp() and inp() won't do it (I tried it with the remote possibility NI had rewritten the functions to work with PCI addresses).
Ed Yoho