Integration Guide

HARDWARE INTEGRATION RECOMMENDATIONS
HOST COMMUNICATIONS SIGNALS
MODULE INTEGRATION GUIDE PROPRIETARY 9
SEQUANS Communications
3.2.2 Other Hardware Considerations
• When considering the placement of the SIM connector and Monarch SIM
interface, try to keep the distance between them as small as possible. This
is to avoid supply trace inductance buildup which could cause unexpected
SIM VCC supply drops under specific SIM control situations. If it is
unavoidable, then be sure to add 4.7µF decoupling capacitor at the SIM
connector itself to act as a charge reserve in help in such situations.
• Please ensure that a good ground return exists between the SIM card and
the VZM20Q.
• If the application requires the support of the hot insertion or removal of
SIM card, then the SIM card handler must include a removal/insertion pad
detector in order to allow the software to process the event immediately.
• The software support of the “hot removal” feature is not currently avail-
able. Please contact your Sequans’ representative for details.
3.2.3 Software-Configurable Options
Note: The content of this section will be provided in a future revision of
the document.
3.3 Host Communications Signals
3.3.1 Introduction to UART Interfaces
The communication between the VZM20Q and the host platform is supported
as follows by 3 UART interfaces.
• UART0 is dedicated to Host-Modem interface
• UART1 is an optional additional Host-Modem interface. It is reserved for
future use.
• UART2 is reserved for debug usage and Sequans’ manufacturing and hard-
ware qualification tools such as DMTool or DVTool.
The following sections detail those interfaces.