In this post, we’re going to take a quick look at the microSD card blob prototype and cover all the information you need to use it in your projects. We’re also going to interface it to a Piksey Nano and create a demo sketch to obtain the SD card information along with the file/directory information.
The blob can be directly interfaced with a 5V microcontroller using the SPI interface as it contains a 5V to 3.3V LDO regulator as well as the necessary level shifters for the data/clock lines.
The LDO can supply a maximum current of 250mA and this needs to be kept in mind if it used to provide power to any other modules.
The blob also supports the faster, 4-bit communication mode but you would need to add the appropriate level shifting for the other bits if you are using it with a 5V microcontroller like the Pico or Nano.
As can be seen above, the silkscreen provides the pin out of the blob. For this demo we only need to connect the following pins:
- Connect D3 to D10
- Connect CMD to D11
- Connect D0 to D12
- Connect CLK to D13
- Connect 5V & GND to the appropriate pins on the microcontroller
Here’s an image of the assembled prototype that’s connected to a Piksey Nano using a breadboard.
We’re not going to go over the sketch in this post as it has been taken from a regular SD card demo sketch.
Once you connect the blob as described earlier, you need to insert a microSD card and upload the program. You can then open up the serial monitor from within the Arduino IDE (Tools -> Serial Monitor) and hit the reset button on the board. You should then be able to see the microSD card information, followed by the file/directory data.
An example of the output has been shown below:
Once you get this basic demo working, you can then modify it to suit your own projects.