Intel cPCI-7200 User Manual

Page 53

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C/C++ Libraries

45

5.13 _7200_Alloc_DMA_Mem

@ Description

Contact Windows 95/98 system to allocate a block of contiguous memory
for single-buffered DMA transfer. This function is only available in Windows
95/98.

@ Syntax

Visual C++ (Windows 95)

int W_7200_Alloc_DMA_Mem (U32 *buff, U32 *handle, U32

buf_size, U32 *actual_size)

Visual Basic (Windows 95)

W_7200_Alloc_DMA_Mem (buff As Long, handle As Long, ByVal

buf_size As Long, actual_size As Long ) As Long

@ Argument

buff:

The start address of the user buffer for DMA data transfer. This buffer

will be attached to the DMA memory allocated by this function. When using
this DMA memory handle as an argument of the W_7200_DI_DMA_Start
function, DI data will be copied to this buffer. When using this DMA memory
handle as an argument of the W_7200_DO_DMA_Start function, the data
stored in this buffer will be the DO data.
handle:

The handle of system DMA memory returned from system. Use this

handle in _7200_DI_DMA_Start or _7200_DO_DMA_Start.
buf_size:

Bytes to allocate. Please be careful, the unit of this parameter is

BYTE, not SAMPLE.
actual_size:

The actual size system allocate for DMA memory. The unit is

BYTE. If system is not able to get a block of contiguous memory of specified
buf_size

, it will allocate a block of memory as large as it can. In this case,

this function returns ERR_SmallerDMAMemAllocated, and actual_size
denotes the actual size of allocated memory.

@ Return Code

ERR_NoError

ERR_SmallerDMAMemAllocated

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