Specifications

Cinterion
®
EXS62-W/EXS82-W Hardware Interface Description
2.4 Sample Application
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2.4 Sample Application
Figure 31 shows a typical example of how to integrate a EXSx2-W module with an application.
Usage of the various host interfaces depends on the desired features of the application.
Note that the sample application is not optimized for low current consumption.
Because of the very low power consumption design, current flowing from any other source into
the module circuit must be avoided, for example reverse current from high state external control
lines. Therefore, the controlling application must be designed to prevent reverse current flow.
Otherwise there is the risk of undefined states of the module during startup and shutdown or
even of damaging the module.
Because of the high RF field density inside the module, it cannot be guaranteed that no self
interference might occur, depending on frequency and the applications grounding concept. The
potential interferers may be minimized by placing small capacitors (47pF) at suspected lines
(e.g. RXD0, TXD0, and ON).
While developing SMT applications it is strongly recommended to provide test points
for certain signals, i.e., lines to and from the module - for debug and/or test purposes.
The SMT application should allow for an easy access to these signals. For details on
how to implement test points see [5] and [7]. Possible test points are mentioned in Sec-
tion 2.1.2.
The EMC measures are best practice recommendations. In fact, an adequate EMC strategy for
an individual application is very much determined by the overall layout and, especially, the po-
sition of components. For example, mounting the internal acoustic transducers directly on the
PCB eliminates the need to use the ferrite beads shown in the sample schematic.
Depending on the micro controller used by an external application EXSx2-W‘s digital input and
output lines may require level conversion. Section 2.4.1 shows a possible sample level conver-
sion circuit.
Disclaimer
No warranty, either stated or implied, is provided on the sample schematic diagram shown in
Figure 31 and the information detailed in this section. Functionality and compliance with nation-
al regulations depend to a great amount on the used electronic components, and the individual
application layout manufacturers are required to ensure adequate design and operating safe-
guards for their products using EXSx2-W modules. Because of the number of frequencies used
it is recommended to involve antenna vendors already quite early to maximize performance of
the external application’s layout.