Docs: National Instruments PCI-6533 Digital I/O Card

Introduction

The ERPSS Acquisition program requires a National Instruments PCI-6533 Digital I/O Card for operation. This card, along with the NI SCB-68 shielded connector box, handles the incoming digital event and response codes. As a new code arrives at the input port, an internal "change detection" event causes the new code to be buffered in a FIFO, and a corresponding "code received" signal to be sent to the PCI-6071e card so that the code arrival time can be "marked" in the EEG data stream. In this way, event codes from one input device and EEG data from another are synced in "real-time" using the features of the hardware, allowing the slower software processes to "catch up" whenever they get the opportunity.

Overview

The NI PCI-6533 card is shown below:

This PCI card must be installed in the Acquisition PC in order to collect digital event and response codes from various devices. Currently, only one 8-bit input port is being used, as both event codes and response codes are being sent from a single Presentation PC device. The single port is configured for change detection, meaning that each time at least one of the eight data lines changes state, a new code is input into the FIFO and a signal is sent to the PCI-6071e to request that it note the time-of-event. Note: Each valid event or response code should be followed by a 0, so that two back-to-back identical codes get registered as two separate events! Otherwise, the arrival of the second identical event gets missed since there is no change detected on the data lines. To avoid this problem, make sure every valid event code is followed by a 0 event.