Moduł SD 3.3V / 5V ARDUINO STM32 LPC

• The LC board has a 5v -> 3.3v regulator IC.
• That's why the 3.3v pin is not connected.

The MISO pin on the LC board is an output and goes directly to the Arduino, so no level shifting is necessary.

• The meanings of the pin designations:
• CS   = Chip Select
• MOSI = Master Out, Slave In
• MISO = Master In,  Slave Out
• SCK  = Slave Clock

Really, folks, it's not about slavery or S&M. A master is the controlling device, and the slave is the device getting signals from the master. Sorry about the unsettling connotations, but it's all engineering jargon, that is,  geekspeak, so to speak.

As noted in a previous step, higher-capacity SD cards may not work because our point-to-point wiring might add noise and delays to the signal lines.

Try one of your old 1 or 2 GB cards. Almost all the examples that come with the Arduino SD library work with our DIY shield. Only the "SD Card read/write" example fails, possibly due to timing considerations because of point-to-point wiring.