ICSP - SPI header on reference board - 5 Volt PSU pin - SPI signals 5 Volt compatible?

[FrankVanWeerdenburg]

The CRB of D2000 has ICSP header. For example to connect SPI to an Arduino WIFI shield.

This header is also used on Galileo - Quark X1000 board.

On Galileo board the SPI signals are converted from 3.3 Volt to 5 Volt level.

The CRB of Quark D2000 does not have this voltage level conversion.

Can you explain this different implementation?

[FrankVanWeerdenburg]

Oops, I just found the answer to my question: The Quark D2000 has 5 Volt tolerant I/O, which is not the case for the Quark X1000.