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Recommendations for using the CD pin as the main switch in a system with a SIM card

ZeroCool2023 , 11-29-2024, 03:34 AM
Hello friends! This might be a very simple question, but I would like to hear your opinions on what you would recommend. I have a SIM card connector, and I want the CD pin to act as the main switch for my entire system. That is, when I insert the SIM, the system should turn on, and when I remove it, everything should turn off. What would you recommend?
QDrives , 11-29-2024, 03:00 PM
Not everybody knows every (or even anything) on SIM cards and related components (ie connector).
Do you have documentation of these as well?
ZeroCool2023 , 11-30-2024, 03:41 AM
Sure, the pinout details are as follows:

C1 - VCC: Power supply for the SIM card.
C2 - RST: Reset pin.
C3 - CLK: Clock signal for synchronization.
C5 - GND: Ground.
C6 - VPP: Voltage for programming (if applicable).
C7 - I/O: Data communication channel between the device and the SIM card.
C4 and C8: These may be pins for insertion detection or for additional functions, although they are not explicitly mentioned in the datasheet.
CD (Card Detect): Function to detect whether the SIM card is inserted or not. From what I can see, C8 could be used as CD.
What I suggest is connecting pin C8 to a transistor to act as the switch to control the entire system.
Robert Feranec , 11-30-2024, 06:44 AM
you can do that, but I would be careful about glitches during card insertion or removal (and possibly other issues that can come up). ideally I would probably build a small test circuit and connected it between the card CD and power button on a similar development kit.
QDrives , 11-30-2024, 04:04 PM
Besides the comments of @Robert Feranec it seems that your data(sheet) is not extensive in details also regarding the card detect.
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