USB

GSM Module

The 2G GSM modules (MT2503, MT6261, RDA8955) provide a USB 1.1 interface with the CDC(ACM) profile. The USB port allows the device to interface with a USB host for communication.

Only the following GSM modules provide USB access:

MC20U
SIM868
M590
A9/A9G

The USB serial port is registered as a device file /dev/ttyUSB0 which can be used as standard UART port.

4G LTE Module

Both the RDA8910 and ASR160x chipsets provide two USB serial ports for user applications. The two device files are registered as /dev/ttyUSB0 and /dev/ttyUSB1.

There are no USB-specific APIs for USB serial port access. The device file supports standard system calls for IO operations and the termios API for serial port parameter controls.

For access to USB serial ports, refer to the UART API.

Example Usage

#include <unistd.h>
#include <fcntl.h>
#include <termios.h>

/* Open USB Uart */
int fd = open("/dev/ttyUSB0");

/* write on USB Uart */
write(fd, "Test", 4);

/* read */
int ret;
char buf[10];

ret = read(fd, buf, sizeof(buf));

Application Example

waybyte/example-uart

API Reference

Header File

Source: include/hw/usb.h

#include <hw/usb.h>

Functions

int usb_is_connected(void)

Get USB cable connect status.

Returns:: 1 if connected, 0 if unconnected