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I need to use a camera module along with De1-SoC development board. Camera requires 3.3V to work and it provides outputs with a 2.5V output pin.

I am trying to find what is the range of voltages that the FPGA will detect. I can not find that information easily anywhere in the specifications or any datasheets. This is the only official help I have found in the DE1-SoC User Manual. If the detection range for '0' is 0V-1.5V, and for '1' is 2.2V-5V I should be able to just plug the camera straight to the FPGA. Otherwise I would need to add additional voltage shifters.

If someone could point me to where I can find information regarding the official input detection characteristics I would be very grateful.

This is the link to the De1-Soc manual, and this is cyclone V manual from which I am too trying to fish out that information.

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  • \$\begingroup\$ How about a link to the data sheet? \$\endgroup\$ – Andy aka Feb 27 '17 at 11:47
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    \$\begingroup\$ You'll find the Altera FPGA part number in the DE1-SoC board manual. Then head to the Altera website for the FPGA data sheet and you'll be able to find the electrical characteristics in there, including your threshold. \$\endgroup\$ – TonyM Feb 27 '17 at 11:50
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Cyclone V pins are configurable for numerous different standards. Look into Cyclone V Device Handbook Vol.1 in chapter 5. Specifially, JEDEC Standard JESD8-5 (that is "2.5V low voltage CMOS") is supported.

From the De1-SOC-Schematics (download CD.zip from Terasic) you can see, that all banks have \$VCC_{IO}=3.3V\$ (except the HPS-banks which use \$1.5V\$). Pins on these banks will correctly detect 2.5V CMOS input (see "I/O Standards Voltage Levels"), but they will not be able to generate 2.5V output.

In general, Alteras Device Handbook (at least Vol.1) is a recommended read, if you want to put your board to use.

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Also, the final answer as to the input and output capabilities for each pin will be found in the project's .qsf file. Here you will find entries like:

set_instance_assignment -name IO_STANDARD "3.3-V LVTTL" -to i_serIn

set_instance_assignment -name CURRENT_STRENGTH_NEW 8MA -to o_LED[0]

and so forth to let you know what that FPGA program intends for the pin. As @Andraes mentions, though, you can't get a 2.5V output from a pin that is powered in a 3.3V bank. The input will be OK if the camera drives hard to VCC.

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