ADLINK PCM-9112+ - Manual (Page 65)

C/C++ Library • 57
3. After the A/D conversion has started, the A/D converted data is
stored in the FIFO of the PCI controller. Each bus mastering data
transfer continually tests if any data in the FIFO and then blocks
transfer, the system will continuously loop until the conditions are
satisfied again but will not exit the block transfer cycle if the block
count is not complete. If there is momentarily no A/D data, the PCI-
9112 will relinquish the bus temporarily but returns immediately when
more A/D samples appear. This operation continues until the whole
block is done.
4. This operation proceeds transparently until the PCI controller transfer
byte count is complete. All normal PCI bus operation applies here
such as a receiver, which cannot accept the transfers, higher priority
devices requesting the PCI bus, etc. Remember that only one PCI
initiator can have bus mastership at any one time. However, review
the PCI priority and "fairness" rules. Also study the effects of the
Latency Timer. And be aware that the PCI priority strategy (round
robin rotated, fixed priority, custom, etc.) is unique to your host PC
and is explicitly not defined by the PCI standard. You must determine
this priority scheme for your own PC (or replace it).
5. The interrupt request from the PCI controller can be optionally set up
to indicate that this longword count is complete although this can also
be determined by polling the PCI controller.
@ Syntax
Visual C++ (Windows-95)
int W_9112_AD_DMA_Start (int card_number, int auto_scan,
int ad_ch_no, int ad_range, int count, HANDLE memID,
int c1, int c2)
Visual Basic (Windows-95)
W_9112_AD_DMA_Start (ByVal card_number As Long, ByVal
auto_scan As Long, ByVal ad_ch_no As Long, ByVal
ad_range As Long, ByVal count As Long, ByVal memID
As Long, ByVal c1 As Long, ByVal c2 As Long) As
Long
C/C++ ( DOS)
int _9112_AD_DMA_Start (int card_number, int auto_scan,
int ad_ch_no, int ad_range, int count , unsigned
long *ad_buffer, int c1,int c2)