National Instruments 321645c-01 用户手册
Chapter 2
Function Reference — DIG_Block_Out
NI-DAQ FRM for PC Compatibles
2-152
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National Instruments Corporation
DIG_Block_Out
Format
status = DIG_Block_Out (deviceNumber, group, buffer, count)
Purpose
Initiates an asynchronous transfer of data from memory to the specified group.
Parameters
Input
Parameter Discussion
group is the group to be written to.
Range:
1 or 2 for most devices.
1 through 8 for DIO-96.
1 through 8 for DIO-96.
buffer is an integer array containing your data. NI-DAQ writes the data in this array to the
group indicated by group. For the DIO-32F and DIO 6533 (DIO-32HS) devices, NI-DAQ
uses all 16 bits in each buffer element. Therefore, the size of the array, in bytes, must be at
least count multiplied by the size of group. For all other devices, NI-DAQ uses only the lower
8 bits of each buffer element. Therefore, the size of the array, in bytes, must be at least twice
count multiplied by the size of group.
group indicated by group. For the DIO-32F and DIO 6533 (DIO-32HS) devices, NI-DAQ
uses all 16 bits in each buffer element. Therefore, the size of the array, in bytes, must be at
least count multiplied by the size of group. For all other devices, NI-DAQ uses only the lower
8 bits of each buffer element. Therefore, the size of the array, in bytes, must be at least twice
count multiplied by the size of group.
count is the number of items (for example, 8-bit items for a group of size 1, 16-bit items for
a group of size 2, and 32-bit items for a group of size 4) to be transferred from the area of
memory specified by buffer to the group indicated by group.
a group of size 2, and 32-bit items for a group of size 4) to be transferred from the area of
memory specified by buffer to the group indicated by group.
Range:
2 through 2
32
– 1.
Using This Function
DIG_Block_Out
initiates an asynchronous transfer of data from your buffer to a specified
group. The hardware is responsible for the handshaking details. Call
DIG_Grp_Config
for
the DIO-32F and the DIO 6533 devices, or
DIG_SCAN_Setup
for the other devices at least
once before calling
DIG_Block_Out
to select the group configuration for handshaking.
Name
Type
Description
deviceNumber
i16
assigned by configuration utility
group
i16
group
buffer
[i16]
array containing the user’s data
count
u32
number of items to be transferred