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Interfacing with a temperature sensor and recording the data is a very difficult task with FPGA from scratch..
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With respect to the DE0-nano, this is probably true. The sensors on the DE0-nano use I2C. I2C is much easier to deal with using an on-board processor. So that would entail coming to grips with the NIOS core and IDE.
An alternative that is more inline with your oscilloscope and triggering concept is to use an external ADC. If you're not too worried about the sampling speed at this point, start with an SPI ADC. You might be able to find an SPI ADC in a DIP package and then plug it into a 100-mil spacing proto board. If you cannot, then buy an SOIC packaged device and use a SchmartBoard adapter
http://www.mouser.com/schmartboard/204-0004-01/ I recently used these to interface some Spansion SPI flash to the DE0-nano. I then used 100-mil jumpers to connect the proto board to the DE0-nano headers (so if you don't have those, you might want to buy some when you order the ADC and SchmartBoard).
The advantage of using an SPI ADC is that you can 'stream' samples, which is much more like your oscilloscope design. You can then design trigger logic. The SPI ADC results can be streamed into on-FPGA RAM, or to the off-chip SDRAM, into a loop buffer. The trigger logic can then decide when to stop streaming. The tutorial I sent you a link to has the means for getting the data off the board.
Cheers,
Dave
Honored Contributor
