Omega 1002 manual 1 A/D Conversion Trigger Modes

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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