INT32S DRV_WritePortByte ( PTR_T DeviceHandle, PT_WritePortByte *lpWritePortByte );
On the device indicated by the DeviceHandle, it writes a byte to a specified I/O port. The port specifies the absolute I/O address, which is valid only within the range of space allocated by the system.
Some parameters, such as specified I/O port address (port) and read back status (ByteData), are stored in the PT_WritePortByte structure pointed by the lpWritePortByte.
| Name | Direction | Range | Description |
| DeviceHandle | input | default | The pointer retrieved from the DRV_DeviceOpen which specifies the target device. |
| lpWritePortByte | input / output | default | Pointer to the user-prepared structure PT_WritePortByte that stores the specified I/O port address (INT16U port) and read back status (INT16U ByteData). |
| 1. 0 | Successful. |
| 2. InvalidDeviceHandle | The DeviceHandle is NULL. |
| 3. Other value | Please reference ErrorCodes |