SDHC card detection pin

[Rahul Soni]

Is is mandatory to use CD pin of SDHC interface. In my processor, SDHC_CD pin is multiplexed with IIC_CLK (I2C CLOCK) and I want to use both IIC and SDHC. Can I use this pin as I2C_CLK. Will it effect SDHC protocol if I use this pin as IIC+CLK instead of SDHC_CD?

 

[FvM]

Are you asking about the processor pin or the card pin?

In case you are using 4-bit SD mode, CD/DAT3 is a mandatory pin which must be connected to the dedicated processor interface pin.
It can be unconnected for 1-bit SD mode.

In SPI mode, the pin works as CS and must be used, but would be connected to a GPIO.

 

[Rahul Soni]

I am asking about processor pin. CD pin is not multiplexed with DAT3 ... Ir is multiplexed with IIC pin ... processor is ls2085.

 

[FvM]

CD/DAT3 is a single SD card pin.

 

[Rahul Soni]

Is it mandatory to use CD pin ?

 

[FvM]

The definition of CD pin with the Freescale processors seems to lay outside the SDHC specification. The processor is e.g. providing a 8-bit data interface which could be used for MMC but not SDHC.

I answered the question from the SDHC perspective, I don't know the requirements imposed by the Freescale interface operation.