Intel PCI-7200 - Manual (Page 33)

Operation Theorem
• 23
4
Operation Theorem
In PCI-7200, there are four data transfer modes can be used for digital I/O
access and control, these modes are:
1. Direct Program Control: the digital inputs and outputs can be read/written
and controlled by its corresponding I/O port address directly.
2. Internal Timer Pacer Mode: the digital input and output operations are
paced by internal timer pacer and transferred by bus mastering DMA.
3. External Clock Mode: the digital input operation is clocked by external
I_REQ strobe and transferred by bus mastering DMA.
4. Handshaking: through REQ and ACK signals, the digital I/O can have
simple handshaking data transfer.
4.1 Direct Program Control
The digital I/O operations can be controlled by I/O port BASE+10 for digital
input and BASE+14 for digital output.
The I/O port address BASE is assigned by system BIOS, please refer to
Section 5 for more detailed description.
The digital OUT operation is:
outport (BASE+14, 0xAAAAAAAA ) // (A : 0 ~ F)
The digital IN operation is:
value = inport (BASE+10) // The input status is save in the
// value variable