Moxa V2406-24I-T-XPE [52/81] Device api

V2406/2422/2426 Linux User’s Manual Programming Guide

4-2

Device API

The V2406/2422/2426-LX supports control devices with the ioctl system API. The interface is shown below:

int ioctl(int d, int request,…);

Input:

<d> open device node return file handle

<request> argument in or out

Refer to desktop Linux’s man page for detailed documentation:

#man ioctl

RTC (Real Time Clock)

The device node is located at /dev/rtc. The V2406/2422/2426-LX supports standard Linux simple RTC control.

You must include <linux/rtc.h>.

1. Function: RTC_RD_TIME

int ioctl(fd, RTC_RD_TIME, struct rtc_time *time);

Description: read time information from the RTC. It will return the value on argument 3.

2. Function: RTC_SET_TIME

int ioctl(fd, RTC_SET_TIME, struct rtc_time *time);

Description: set RTC time. Argument 3 will be passed to RTC.

UART

The normal tty device nodes are /dev/ttyS0 and /det/ttyS1. The V2406/2422/2426-LX supports standard

Linux termios control with RS-232/422/485 serial ports. Take the following steps to configure the serial ports:

1. You must include moxadevice.h, which you can find in the folder \example\moxalib on the CD.

#define RS232_MODE 0

#define RS485_2WIRE_MODE 1

#define RS422_MODE 2

#define RS485_4WIRE_MODE 3

2. Function: MOXA_SET_OP_MODE

int ioctl(fd, MOXA_SET_OP_MODE, &mode)

Description: Set the interface mode. Argument 3 mode will pass to the UART device driver and change it.

3. Function: MOXA_GET_OP_MODE

int ioctl(fd, MOXA_GET_OP_MODE, &mode)

Description: Get the interface mode. Argument 3 mode will return the interface mode.

There are two Moxa private ioctl control definitions for setting up special baudrates.

MOXA_SET_SPECIAL_BAUD_RATE

MOXA_GET_SPECIAL_BAUD_RATE

If you use this ioctl to set a special baudrate, the termios cflag will be B4000000, in which case the

B4000000 define will be different. If the baudrate you get from termios (or from calling tcgetattr()) is

B4000000, you must call ioctl with MOXA_GET_SPECIAL_BAUD_RATE to get the actual baudrate.