Sim card + RTC + on/off pin implementation

  1. About sim card. From Tech. guide of WMP100 page 51(3.10.3 Application) for proper sim card attachment to the module
    a) I need to implement the D1(ESDA6VISC6 from ST) and D2 (DALC208SC6 from SGS-Thomson).
    The D1&D2 come in between the WMP100 and sim card
    Question: what if I will skip this D1&D2 components will the sim card work ?

  2. About RTC. From Tech. guide of WMP100 page 100 :
    “The pin “XIN_32K”(AC24) and pin “XOUT_32K” are used to connect a crystal which is MANDATORY to setup and
    run the WMP100 module”
    Question: Is the word mandatory mean that without connecting that crystal I won’t be able to turn module on, download the firmware
    and my application ?

  3. About on/off pin(U5). From Tech. guide of WMP100 page 85 (3.17)
    “The voltage on pin on/off has to be maintained at 0.8xVBATT for 1500 ms to turn the module on”.
    Question: what does 0,8xVBATT mean? Can I just connect “VBATT” pin with “on/off” pin like it show on page 86(Figure36) ?


Yes, “mandatory” means “compulsory” or “essential”, etc - it means you do not have the option to omit the crystal.

If you omit the crystal, it won’t work.

These diodes must be considered as mandatory. The provided references are just recommanded, meaning that you can use similar components.

Absolutely, without this crystal, the WMP100 will not work

Yes, you can. Have a look to ON/OFF Electrical characteristics table, on chapter 3.17.1 .


I guess what they really mean is, "The voltage on pin on/off has to be maintained at at least 0.8xVBATT…" :question: