National Instruments PCI-8430, Руководство пользователя

Страница: 119 / 237

Setting the RS-232 Transceiver Mode with
DeviceIoControl
There are two ways to set and retrieve the RS-232 transceiver state:
Set and read the NI-VISA wire mode attribute.
The NI-Serial software uses programmatic control codes and the
DeviceIoControl Windows function to retrieve the RS-232
transceiver state.
To set and retrieve the RS-232 transceiver state using the
DeviceIoControl Windows function, complete the following steps:
1. Add the following lines to your source code:
#include <winioctl.h>
#include <NiSerial.h>
Note The header file NiSerial.h is included on your NI-
Serial software CD. You also can find it in the
NI-Serial
folder where you installed your National Instruments
software (typically,
C:\Program Files\National Instruments\NI-
Serial
).
2. The
TRANSCEIVER_MODE
attribute can have the following
values:
RS232_MODE_DTE
RS232_MODE_DCE
RS232_MODE_AUTO
3. To set the RS-232 transceiver, use
NISERIAL_SET_RS232_MODE
and DeviceIoControl. For example, to set to Force DCE mode,
use the following code:
TRANSCEIVER_MODE l_TransceiverMode = RS232_MODE_DCE;
DWORD l_ByteCount;
DeviceIoControl (