4.4 A/D Conversion
An A/D conversion can be initiated three different ways: software command, internal
programmable interval timer or external trigger. At the end of the A/D conversion, it is
possible to transfer the data by polling a status register and reading the data when ready or
by generating a hardware interrupt and an interrupt service routine. All modes are selected
by a control register on the OME-PCI-1002 and are supported by the utility software.
Below are key points for successfully collecting A/D data:
z
A/D data register, BASE+30h, stores the A/D conversion data.
z
A/D data conversion ready register, BASE +10h. Check if A/D data is ready.
z
A/D gain control register, BASE+14h, select gain.
z
A/D multiplexer control register, BASE+10h, select analog input
channel.
z
A/D mode control register, BASE+0Ch, select trigger type and transfer type.
z
A/D software trigger control register, BASE+1Ch
.
z
JP1 select single-ended or differential input.
z
3 Triggers: Software, Pacer, and External trigger.
z
2 Transfer Modes: Polling and Interrupt.
The block diagram is given follows:
BASE+1Ch
Software Trigger
BASE+10h BASE+14h
Trigger
Logic
CPU
BASE+30h
Memory
Buffer
12 bits
A/D
Gain
Control
16/8 to 1
Multi-
plexer
CN3
OME-PCI-1002H/L
38
Summary of Contents for OME-PCI-1002
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