FPGA notes (i)

Novice FPGA, a fall into your wit process.

The FPGA Development board used the black Gold Learning Board ALINX301,FPGA model Cycloneiv ep4ce6f17c8n.

Beginners, all from the light of the first LED light start.

Module fisrtled (LED);

Output [3:0] LEDs;

Assign led=4 ' b1010;

Endmodule

Found that the difference is that the 51 single-chip microcomputer used by the current-driven LED,FPGA does not seem to say (do not understand ~).

Look at the schematic:

Directly let FPGA output 3v3 or 1.2V or 2.5V or 2.8V, see the chip manual also see FPGA can set current strength.

The 8ma current is enough to drive a small lamp. Also tried the 4ma drive, is also possible.

After setting up the LED every location in Pins planer, a compilation error occurred.

Error:can ' t place mutiple pins assgined to pin location PIN_F16.

Probably know is not so used to this multi-purpose pin assignment, do not know why.

Take a look at the pin diagram of the FPGA led1:

See F16 This pin has a lot of features, there is no feeling about this error ~ No, Baidu bar. After all, Baidu Ah, everything has!

Solution:

Change the NCEO setting to used as regular I/O with the Assignme-device-device and pin Option-dula Purse pin in quartusii

At this point, the solution is to solve, indeed F16 a function is Nceo, however, there is no feeling, I do not know why this nceo function is why can not give it assign.

Continue Baidu ~

The NCEO is a reusable pin that can be changed to a user I/O PIN when configured in a single configuration, or to a tri-state, the main function of which is to act as an nce pin for the next FPGA in multiple FPGAs, while the NCE is primarily used as the device's chip-selection signal, which is active at low levels.

A blog about this error is more detailed:

Http://www.cnblogs.com/oomusou/archive/2011/02/28/de2_70_dual_pin.html

Continue to be familiar with FPGA ...

FPGA notes (i)