74HC4050 - Buffer on SD

[ohararp]

David, what is the story on the buffer chip for the SD card for the SD shields? I have not had to use one of these before and was curious why you included this when both the Pic and the SD card are running at 3.3V

[David John Barker]

That's a very good question! You are quite right, running at 3.3v there would not normally be any need for a level shifter chip. However, all of the Firewing shields are compatible with Arduino, which runs at 5v. You will see this chip a lot in boards designed for Arduino.

In summary, Firewing shields are pin and voltage compatible with Arduino.