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AMIC120: SITARA

Part Number: AMIC120

I am using AMIC120 SITARA processor in my project as a processor. MMC0 port is using as SD card interface. n24 pin from the AMIC120 processor is using as SD card detect pin.

when no SD card is inserted, detect signal is LOW. when SD is inserted, detect signal is HIGH. is there any problem with this logic??

  • The SD Card specification defines both normally open and normally closed switch options for card detect. The specification also defines the card detect signal must be pulled high with a pull-up resistor and connected to one side of the normally open or normally closed card detect switch with the other side of the card detect switch connected to ground. Therefore, the logic state which you are asking about is a valid option per the SD Card specification.

    The answer to your question is a function of the software you are using. I have been told the Linux driver supported by TI allows a customer to define which GPIO is being used for card detect, but not sure if it provides an option to select polarity.

    The input associated with AMIC120 pin N24 can be routed to the MMCSD host controller via mux mode 0x4 or the GPIO3 module via mux mode 0x7.  In either case the input state can be determined via a register read.  So you need to understand what is supported by the software you are using to answer this question.

    If you are using TI software and need help, I will need to ask someone else to reply.

    Regards,
    Paul