PCI 703 User Manual
Eagle Technology - Data Acquisition
Eagle Technology © Copyright 2001-2004 – www.eagledaq.com
21
Analog Output
The PCI703-X/A version has got 2 DAC channels that support single write and waveform
generation. The DAC subsystem uses the onboard counters for timing and a FIFO for data
transfer. The two DAC channels are controlled independently from each other. The DAC
subsystem is control via 3 functions: SingleWrite, Control and Configure.
Writing to a DAC channel
A single call is necessary to set a voltage on a DAC channel.
API-CALL
Long EDRE_DAWrite (ulng Sn, ulng Channel, long uVoltage)
The serial number, DAC channel and micro-voltage is needed to set a DAC channel’s
voltage. A return code will indicate if any errors occurred.
ACTIVEX CALL
Long EDREDAX.Write (ulng Channel, long uVoltage)
The DAC channel and micro-voltage is needed to set a DAC channel’s voltage. A return code
will indicate if any errors occurred.
Generating a Waveform
Generating a waveform is basically a two-step process. First configure a channel then start
and stop it. Two modes are available, FIFO non-loop mode and pattern mode. FIFO non-loop
the FIFO data only gets outputted once. The DAC output voltage will be the same as the last
value in the FIFO. In pattern mode the FIFO data is outputted continuously. Please note that
the frequency is not the total frequency of the waveform, but the update rate of the DAC
channel. This is the value written directly to the counter.
Update frequency = (Internal clock frequency) / (counter value +1)
API-CALL
Long EDRE_DAConfig (ulng Sn, ulng Channel, ulng Frequency, ulng ClkSrc, ulng
GateSrc, ulng Continuous, ulng Length, long *uVoltage)
Parameter
Type
Description
Sn
Unsigned long
Board’s serial number
Channel
Unsigned long
Channel
0: DAC Channel 0
1: DAC Channel 1
Frequency
Unsigned long
Actual value written to counter
ClkSrc
Unsigned long
Clock source
0: Internal 20 MHz
1: Internal 100 KHz
2: External Clock
GateSrc
Unsigned long
Gate Source – Ignored
Continuous
Unsigned long
Mode
0: NON LOOP MODE
1: LOOP MODE
Length
Unsigned long
Buffer length
uVoltage
Pointer to a long buffer
Buffer filled with micro voltages
Return
Long
Error Code
ACTIVEX CALL
Long EDRDAX.Configure (long Channel, long Frequency, long ClkSrc, long GateSrc,
long Continuous, long Length, long *uVoltage)
Parameter
Type
Description
