Omega 1002 - Manual (Page 40)

4.4.1 A/D Conversion Trigger Modes
The OME-PCI-1002 supports three trigger modes.
1 : Software Trigger :
Write any value to A/D software trigger control register, BASE+1Ch, will initiate a
A/D conversion cycle. This mode is very simple but very difficult to control
sampling rate.
2 : Pacer Trigger Mode :
The block diagram of pacer timer is shown in section 3.2. The sample rate of pacer
is very precise.
3 : External Trigger Mode :
When a rising edge of external trigger signal is applied, an A/D conversion will be
performed. The external trigger source comes from Pin-17 of CON3.
4.4.2A/D Transfer Modes
OME-PCI-1002 supports two transfer modes.
1 : polling transfer :
This mode can be used with all trigger modes. You must disable timer 0 before
polling. The A/D data can be read from the register at BASE+30h. Before reading
the data first check the A/D ready bit at register BASE +10h READY_BIT=0.
2 : interrupt transfer:
This mode can be used with the pacer trigger or an external trigger. A hardware
interrupt signal is sent to the PC when an A/D conversion is completed.
For interrupt transfer, the use of the driver software is strongly recommended.
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