Specifications

Operation Theorem •• 23

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.