User`s guide

C/C++ Libraries • 57
@ Return Code
NoError
AllocDMAMemFailed
5.13 _7300_Free_DMA_Mem
@ Description
Deallocate a system DMA memory under Windows 95 environment. This
function is only available in Windows 95 version.
@ Syntax
Visual C/C++ (Windows 95)
int W_7300_Free_DMA_Mem (HANDLE memID)
Visual Basic (Windows 95)
W_7300_Free_DMA_Mem (ByVal memID As Long ) As Long
@ Argument
memID: The memory ID of the system DMA memory to
deallocate.
@ Return Code
NoError
5.14 _7300_DI_DMA_Start
@ Description
The function will perform digital input by DMA data transfer.
It will take place in the background which will not stop until the N-th input data
is transferred or your program execute the
_7300_DI_DMA_Abort
function to
stop the process.
After executing this function, it is necessary to check the status of the operation
by using the function
_7300_DI_DMA_Status
. The PCI-7300A Bus
mastering DMA is different from traditional PC style DMA. Its description is as
follows:
Bus Mastering DMA mode of PCI-7300A:
PCI bus mastering offers the highest possible speed available on the
PCI-7300A. When the function
_7300_DI_DMA_Start
is executed, it will
enable PCI bus master operation. This is conceptually similar to DMA (Direct
Memory Access) transfers in a PC but is really PCI bus mastering. It does not