SIM5218E Hardware Design
Typical charge curves for each cell type are shown in following figures. Note that the rechargeable
Lithium type coin cells are generally come pre-charged from the vendor.
Figure 11: Seiko MS518 Charge and discharge Characteristic
Note:
Gold-capacitance backup
Some suitable coin cells are the electric double layer capacitors. They have a small physical size
(6.8 mm diameter) and a nominal capacity of 0.2 F to 0.3 F, giving hours of backup time.
3.7 Serial interface
SIM5218E provides an unbalanced asynchronous serial port. The module is designed as a DCE
(Data Communication Equipment), following the traditional DCE-DTE (Data Terminal
Equipment) connection, the module and the client (DTE) are connected through the following
signal (as following figure shows).
In order to prevent the UART signals of the module damaged due to voltage spikes or ESD, some
resistors can be added on UART signals. The values of resistors are
adjusted
according to the
actual circuit. The resistors
should be placed close to the module.
The application circuit is in the following figures.
SIM5218E_ Hardware Design_V1.06
2012.09.21
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Содержание SimCom SIM5218E
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