National Instruments 653 Series User Manual page 101

Appendix C Connecting Signals with Accessories
Pins Signal Name
2, 9 REQ<1..2>
3, 8 ACK<1..2>
STARTTRIG
<1..2>
4, 7 STOPTRIG
<1..2>
5–6 PCLK<1..2>
10, 44–45, DIOA<0..7>
12–13,
47–48, 15
16–17, DIOB<0..7>
21–22,
51–54
NI 653X User Manual
Table C-3. Signal Descriptions
Signal
Type
Control Group 1 and group 2 request lines
Handshaking I/O—Request. A control line that indicates whether the
peripheral device is ready to transfer data.
Pattern I/O—REQ carries timing pulses either to or from the peripheral
device. These strobe signals are comparable to the CONVERT* or UPDATE*
signals of an analog DAQ device.
Unstrobed I/O—Option to use REQ<1..2> as extra, general-purpose input
lines (IN<3..4>).
Control Group 1 and group 2 acknowledge lines
Handshaking I/O—Acknowledge, a control line that indicates whether the
NI 653X is ready to transfer data.
Pattern I/O—Used as a start trigger (STARTTRIG<1..2>) line. You can start
pattern I/O operations upon the rising or falling edge of a signal on these lines.
Unstrobed I/O—Option to use the ACK<1..2> lines as extra,
general-purpose output lines (OUT<3..4>).
Control Group 1 and group 2 stop triggers
Handshaking I/O—Not used.
Pattern I/O—Used in trigger operations as stop trigger. You can end pattern
I/O operations upon the rising or falling edge on these lines.
Unstrobed I/O—Option to use the STOPTRIG<1..2> lines as extra,
general-purpose input lines (IN<1..2>).
Control Group 1 and group 2 peripheral clock lines
Handshaking I/O (Burst Mode)—The only handshaking mode that utilizes
these signals. By default, PCLK is an output during an input operation and an
input during an output operation. PCLK direction is programmable.
Pattern I/O—Not used.
Unstrobed I/O—Option to use the PCLK<1..2> lines as extra,
general-purpose output lines (OUT<1..2>).
Data Port A bidirectional data lines
Port A is referred to as port number 0 in software. DIOA7 is the most
significant bit (MSB); DIOA0 is the least significant bit (LSB).
Data Port B bidirectional data lines
Port B is referred to as port number 1 in software. DIOB7 is the MSB;
DIOB0 is the LSB.
Signal Description Based on Mode Used
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