National Instruments DAQCard-1200 - Manual (Page 57)

Chapter 4 Theory of Operation
DAQCard-1200 User Manual 4-4 © National Instruments Corporation
Figure 4-3. Timing Circuitry
2 MHz
Source
A/D Conversion Logic
1 MHz Source
OUTB0
CLKA0
GATEB0
OUTB0
CLKB1
GATEB1
OUTB2
GATEB2
CLKB2
D/A Conversion Logic
82C53 Counter/Timer
Group A
CTR RD
CTR WRT
Data
8
Decode Cir
cuitr
y
82C53 Counter/Timer
Group B
OUTB0
OUTB2
GATEB2
CLKB2
GATEB1
Scan
Interval/
CLKB1
OUTB1
GATEB0
Timebase
Extension/
CLKB0
+5 V
MUX MUX
EXTUPDATE*
EXTTRIG
EXTCONV*
I/O Connector
CLKA2
OUTA0
Sample
Interval
Counter
CLKA0
GATEA0
CLKA1
Sample
Counter
GATEA1
OUTA1
GATEA2
DAC
Timing
OUTA2
OUTB1
OUTB1
General-
Purpose
Counter
General-
Purpose
Counter
General-
Purpose
Counter