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C/C++ Library
3. After the A/D conversion is started, the A/D converted data is stored in
the FIFO of 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.
u 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)
u Argument
card_number: the card number of PCI-9112
auto_scan: TRUE or FALSE
Example1: auto_scan is FALSE, ad_ch_no is 3. Using DMA mode to
read A/D data only channel 3.
Example2: auto_scan is TRUE, ad_ch_no is 3. Using DMA mode to read
A/D data with multi-channel , channel 3, 2, 1 and 0. Reading sequence is
channel 3,2,1,0, 3,2,1,0,3,2,1,0....