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LISA-U1/LISA-H1 series - System Integration Manual

3G.G2-HW-10002-2 Advance Information System description

Page 55 of 116

If the USB interface of LISA-U1/LISA-H1 series modules is connected to the host before the module switch-on, or

if the module is reset with the USB interface connected to the host, the VID and PID are automatically updated

runtime, after the USB detection. First, VID and PID are the following:

 VID = 0x058B

 PID = 0x0041

Then, after a time period (~5 s), VID and PID are updated to the following:

 VID = 0x1546

 PID = 0x1101

If power saving is enabled by AT command (AT+UPSV=1 or AT+UPSV=2), the LISA-U1/LISA-H1 series module

automatically enters the USB suspended state when the device has observed no bus traffic for a specified period

(refer to the Universal Serial Bus Revision 2.0 specification [7]). In suspended state, the module maintains any

internal status as USB device, including its address and configuration. In addition, the module enters the

suspended state when the hub port it is attached to is disabled: this is referred to as USB selective suspend. The

module exits suspend mode when there is bus activity.

LISA-U1/LISA-H1 series module is capable of USB remote wake-up signaling: may request the host to exit

suspend mode or selective suspend by using electrical signaling to indicate remote wake-up. This notifies the

host that it should resume from its suspended mode, if necessary, and service the external event that triggered

the suspended USB device to signal the host. Remote wake-up is accomplished using electrical signaling

described in the Universal Serial Bus Revision 2.0 specification [7].

1.9.3.2 USB application circuit

Since the module acts as a USB device, the USB supply (5.0 V typ.) must be provided to VUSB_DET by the

connected USB host. The USB interface is enabled only when a valid voltage as USB supply is detected by the

VUSB_DET input. Neither the USB interface, nor the whole module is supplied by the VUSB_DET input: the

VUSB_DET senses the USB supply voltage and absorbs few microamperes.

The USB_D+ and USB_D- lines carry the USB serial data and signaling. The lines are used in single ended mode

for relatively low speed signaling handshake, as well as in differential mode for fast signaling and data transfer.

USB pull-up or pull-down resistors on pins USB_D+ and USB_D- as required by the Universal Serial Bus Revision

2.0 specification [7] are part of the USB pad driver and do not need to be externally provided.

External series resistors on pins USB_D+ and USB_D- as required by the Universal Serial Bus Revision 2.0

specification [7] are also integrated: characteristic impedance of USB_D+ and USB_D- lines is specified by the

USB standard. The most important parameter is the differential characteristic impedance applicable for

odd-mode electromagnetic field, which should be as close as possible to 90  differential: signal integrity may

be degraded if the PCB layout is not optimal, especially when the USB signaling lines are very long.

LISA-U1/LISA-H1 series

VBUS

D+

D-

GND

VUSB_DET

USB_D+

USB_D-

GND

USB DEVICE

CONNECTOR

D1 D2 D3

Figure 30: USB Interface application circuit