VCM-DAS-3 datasheet(39/42 Pages) ETC2

Part #	VCM-DAS-3

Description	The VCM-DAS-3 is a PC/104-format data acquisition board that provides analog outputs and digital I/O for process control and other applications.

PDF	42 Pages

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Manufacturer	ETC2 [List of Unclassifed Manufacturers]

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Enhanced Mode Operations

VCM-DAS-3 Reference Manual

Enhanced Mode Operations

The VCM-DAS-3 must be in enhanced mode to perform enhanced mode operations.

READING DAC DATA

Reading a DAC using the Read DAC operation does not cause the DAC to be updated, as reading

the DACALL0 register does. Performing a Read DAC operation loads the DAC voltage code in

the ENDATHI and ENDATLO registers. To read the voltage of a DAC:

1. Perform a Read DAC operation by writing 8h to the CTRL field of the ENCTRL register

at I/O port 0x30A, combined with the channel number in the SEL field of the same

2. Read the ENDATHI register and then the ENDATLO register. The 12 bits of the output

voltage code are offset toward the MSB, as shown below.

ENDATHI MSB (Read) 0309h

D11

D10

ENDATLO LSB (Read) 0308h

READING THE SPAN OF A CHANNEL

To read the span of a channel:

1. Perform a Read Span operation by writing 9h to the CTRL field of the ENCTRL register

at I/O port 0x30A, combined with the channel number in the SEL field of the same

2. Read the span code from bits 3-0 of the ENDATLO register at I/O port 0x308, as shown

below.

ENDATLO LSB (Read) 0308h

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VCM-DAS-3 Datasheet(PDF) 39 Page - List of Unclassifed Manufacturers