ADLINK PXI-2208 - Manual (Page 90)

78 Operation Theory
You can utilize the flexible timing signals through our software
drivers, then simply and correctly connect the signals with the
DAQ-/DAQe-/PXI-2204/2205/2206/2208 card. Here is the sum-
mary of the DAQ timing signals and the corresponding functional-
ities for DAQ-/DAQe-/PXI-2204/2205/2206/2208 card.
DAQ timing signals
NOTES Refer to section 4.1 for the internal timing signal defini-
tion.
The DAQ-/DAQe-/PXI-2208 card supports
SCAN_START, ADCONV and DA_TRIG, DAWR.
The user-controllable DAQ timing-signals contain:
1. TIMEBASE, providing TIMEBASE for all DAQ opera-
tions, which could be from internal 40 MHz oscillator,
EXTTIMEBASE from I/O connector or the
SSI_TIMEBASE. Note that the frequency range of the
EXTTIMEBASE is 1 MHz to 40 MHz, and the EXTTIME-
BASE must be TTL-compatible.
2. AD_TRIG, the trigger signal for the A/D operation, which
could come from external digital trigger, analog trigger,
internal software trigger, and SSI_AD_TRIG. Refer to
section 4.5 for detailed description.
3. SCAN_START, the signal to start a scan, which would
bring the following ADCONV signals for AD conversion,
and could come from the internal SI_counter, AFI[0] and
SSI_AD_START. This signal is synchronous to the
TIMEBASE. Note that the AFI[0] should be TTL-compat-
ible and the minimum pulse width should be the pulse
Timing signal category Corresponding functionality
SSI/PXI signals Multiple cards synchronization
AFI signals
Control DAQ-/DAQe-/PXI-2204/2205/2206/
2208 by external timing signals
Table 4-8: User-controllable Timing Signals and Functionalities