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Altera_Forum
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15 years ago

Urgent! hardware interface between FPGA DE2 board(3.3V) and ADC(5V)

HI, may i ask your guys a favor. I am using DE2 board for my project and i need to interchange signals(SPI) to an ADC. The ADC is 5V for logic high but the max output signal for DE2 board is only ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

Hi, thanks again for your reply.

While waiting to the HCT, i tried another translator, it work but no up to 1MHz, it is only up to 2ooKHz for the squrewave without turning into sawtooth wave. The HCT f my order haven't reach me yethttp://www.alteraforum.com/images/smilies/mad.gif

http://rapidshare.com/files/371907323/sn7407.pdf.html

May you refer to the the pdf above, page 4 the 1st circuit connection? I constructed according to this but i didn't put the capacitor as i don't need a filter.Thus, i only use the pull up resistor. The Vcc is 5V.

Then there is no problem after output of translator is fine. Problem occurred when i connected to ADC( i supply 2 control signals).The waveform distorted when i combine this translator and ADC.

Please refer to :

http://rapidshare.com/files/371894736/upload.rar.html

I doubt if it is the internal structure of ADC that makes the waveform distorted when 2 signals are transferred. No distortion if only 1 connection is made between ADC and translator but there will be if more than 1 lines are connected.

One more thing, can you let me know about the Vih?