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Altera_Forum
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12 years ago

facing spi intarface DE2

Hello I am very new to Altera and Vhdl pls help I want to conenct micro to Dea2 "gpio" pins and implament spi communication and my qauastion is what kind of voltage level my micro should wo...
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Altera_Forum
Icon for Honored Contributor rankHonored Contributor
12 years ago

Ideally the microcontroller should have 3.3V logic levels.

Probe the signals with an oscilloscope at the DE2 connector and check there is no ringing on the SPI clock signal. If there is, add a series resistor close to the microcontroller board. This will stop the FPGA seeing multiple clock edges.

If you don't have an oscilloscope, then use SignalTap II with a 50MHz clock (whatever the onboard oscillator is) to look at the SPI interface, and zoom into the clock edges to see there is no "glitching".

Cheers,

Dave