3V SPI Interface to micro SD memory cards in 2.54mm pinout
Thanks to mobile revolution, today Micro SD memory cards are available at very low cost(for example a Micro SD 2 GB card at around 200/- INR or $4 USD) so they make ideal choice in embedded projects for data storage and retrieval. More over cards upto 32 GB are also available easily. Many projects like data logger, audio playback etc can be developed.
We have provided an interface boards which accepts any Micro SD Memory Card and provides a 0.1” in standard header for easy connection to any microcontroller system. All SD Card works on 3V interface so if your microcontroller is working on 3V you can use this board readily.
The interface board provided is for microcontrollers running at 3V.
R1, R2 & R3 are pull up 10K resistors as required by SD Card to operate correctly. The CD is card detect signal which tells if a card is inserted or not.
You can see our board circuit diagram below, we have already put the 10K pull up resistor on data pins and 100nf supply capacitor.
Suitable for Micro SD Cards (Same used in mobile phones)