Circuit Extern DE2

[Altera_Forum]

Hello, i want to know if i can connect in the output of de2 a extern circuit, for example : simple circuit with resistors? 

 Thansk

[Altera_Forum]

You can use the two general purpose I/O connectors GPIO0 and GPIO1 to connect te DE2 to your own circuits (including your resistors). The GPIO pins can be programmed as output by which you get either a 3.3 volt or 0 volt output. (By using the jumpers you can also choose an other high output voltage). You can also use the pins as input and then the result read will depend on the voltage at the input pin being higher or lower than the threshold voltage.

[Altera_Forum]

then for example, if i want to use an external 6 segments display i can plug the output of de2 in a protoboard that will send the sinal? 

 thanks

[Altera_Forum]

You can connect a 7 segment display to the GPIOs. But you should limit the current by adding a resistor in series with every LED diode of the 7 segment display. The value of the resistor depends on the amount of current Iled that you want to use for the LED. The voltage drop over your LED will be ~1.45 Volt, the logic signal from the FPGA 3.3 Volt. 

There is already a 47 Ohm series resitor for every output to protect the FPGA for first order "accidents".   Using Ohm's law you can calculate the resistance that you require.   R = ((3.3 Volt - 1.45 Volt) / Iled) - 47 Ohm   e.g. for a LED current Iled = 5 mA this boils down to:   R = ((3.3 - 1.45) / 0.005) - 47 = 323 Ohm   In this case you could use series resistors of 330 Ohm.   It depends of course on the LEDs in the 7-segment displays how much current that should be used.  There is also a limitation on the maximimum current sourcing from your FPGA pins (8 to 24 mA) depending of the I/O standard you use, as well as the combined current sourcing from consecutive pins in I/O banks.      So you could use resistors of 150 Ohm.

[Altera_Forum]

oow now i know! thanks for all