Chapter 4
Programming
© National Instruments Corporation
4-53
AT-DIO-32F User Manual
Pattern Generation Using an External Signal
An external signal connected to the REQ line of a group can be used for pattern generation. The
programming steps to configure Group 1 for 16-bit pattern generation on an external signal are as
follows:
1. Connect the external signal to the REQ1 line.
2. If the external signal is active high pulse, write hex 0638 to the CFG1 Register. If the
external signal is active low pulse, write hex 0678 to the CFG1 Register.
3. Write hex A400 to the CFG3 Register.
4. Write the first pattern to Port A. This operation stores the pattern in the write buffer of the
port.
5. When REQ1 is received, the first pattern loaded in the write buffer of the port is transferred
to the output buffer of the port; therefore, the first pattern is available on the digital I/O
connector.
6. The received REQ1 sets the DRDY1 bit. Write the next pattern to Port A.
7. The next REQ1 received dumps the second pattern to the digital I/O connector.
The sequence continues until an LRESET1 is received.
The programming steps are similar for configuring Group 2 for pattern generation with an
external signal.
Programming the RTSI Bus Interface
The RTSI switch connects signals on the AT-DIO-32F to the seven RTSI bus trigger lines. The
RTSI switch has seven pins labeled A<6..0> connected to AT-DIO-32F signals, and seven pins
labeled B<6..0> connected to the seven RTSI bus trigger lines. The signals connected to each
pin are given in Table 4-6. RWGRP1* and RWGRP2* are board-generated, active low pulse
signals that are 250-nsec to 500-nsec wide. RWGRP1* is the read/write signal for Port A and
Port B. RWGRP2* is the read/write signal for Port C and Port D.
Table 4-6. RTSI Switch Signal Connections
RTSI Switch Pin
Signal Name
Signal Direction
Side A:
A0
RWGRP1*
Output
A1
RWGRP2*
Output
A2
REQ1
Input
A3
REQ2
Input
A4
ACK1
Output
A5
ACK2
Output
A6
IN1
Input
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