Chapter 5 Signal Timing
© National Instruments Corporation 5-5 DIO 6533 User Manual
6533 device emulation mode is a superset of the 8255 and 82C55
protocols. The PCI-DIO-32HS can handshake with peripheral devices
that use 8255 or 82C55 handshaking specifications.
The 6533 device can perform back-to-back transfers much faster than a
true 8255-based device. If your peripheral device requires more time
between transfers, you can configure the 6533 device to add a
data-settling delay between transfers.
You can use a 6533 device in emulation mode with 8, 16, or 32-bit data
paths.
Input
Note: 6533 device terminology differs from 8255 terminology. In input mode,
the 6533 device REQ line carries the 8255 STB input signal, and the
6533 d evice ACK line carr ies the 8255 IBF output signal. Both lines are
active low.