User's Manual

Cinterion
®
ALS6A-E Hardware Interface Overview
3.3 USB Interface
25
 ALS6A-E_HIO_H_v01.270a 2015-03-10
Confidential / Released
Page 22 of 36
3.3 USB Interface
ALS6A-E supports a USB 2.0 High Speed (480Mbps) device interface. The USB interface is
primarily intended for use as command and data interface and for downloading firmware.
The USB host is responsible for supplying the VUSB_IN line. This line is for voltage detection
only. The USB part (driver and transceiver) is supplied by means of BATT+. This is because
ALS6A-E is designed as a self-powered device compliant with the “Universal Serial Bus Spec-
ification Revision 2.0”
1
.
Figure 2: USB circuit
To properly connect the module's USB interface to the external application, a USB 2.0 compat-
ible connector and cable or hardware design is required. Furthermore, the USB modem driver
distributed with ALS6A-E needs to be installed.
While a USB connection is active, the module will never switch into SLEEP mode. Only if the
USB interface is in Detached state (i.e., VUSB_IN = 0) the module is able to switch into SLEEP
mode thereby saving power. In this case the RING0 line can be employed to wake up the ex-
ternal application when events signalized by URCs are detected (incl. incoming SMS). Every
wakeup event will force a new USB enumeration. Therefore, the external application has to
carefully consider the enumeration timings to avoid loosing any signalled events.
1.
The specification is ready for download on http://www.usb.org/developers/docs/
DP
DN
VREG (3V075)
BATT+
USB_DP
3)
lin. reg.
GND
Module
Detection only
VUSB_IN
2)
USB part
1)
1)
All serial (including R
S
) and pull-up resistors for data lines are implemented.
USB_DN
3)
3)
If the USB interface is operated in High Speed mode (480MHz), it is recommended to take
special care routing the data lines USB_DP and USB_DN. Application layout should in this
case implement a differential impedance of 90 ohms for proper signal integrity.
R
S
R
S
VBUS
1µF
2)
Since VUSB_IN is used for detection only it is recommended not to add any further
blocking capacitors on the VUSB_IN line.
Host wakeup
RING0
SMT