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Appendix C Connecting Signals with Accessories
653X User Manual C-4 ni.com
Table C-3. Signal Descriptions
Pins Signal Name
Signal
Type
Signal Description Based on Mode Used
2, 9 REQ<1..2> 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>).
3, 8 ACK<1..2>
STARTTRIG
<1..2>
Control Group 1 and group 2 acknowledge lines
Handshaking I/O—Acknowledge, a control line that indicates whether the
653X device 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>).
4, 7 STOPTRIG
<1..2>
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>).
5–6 PCLK<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>).
10, 44–45,
12–13,
47–48, 15
DIOA<0..7> Data Port A bidirectional data lines
Port A is referred to as port number 0 in software. DIOA7 is the MSB; DIOA0
is the LSB.
16–17,
21–22,
51–54
DIOB<0..7> 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.