CMOD A7 15T programming problem.

[gfellio]

Hi,

I'm new to Vivado and CMOD. I created a very simple program and downloaded it to the board, but it didn't work properly.

In my source VHDL code, I take the two push buttons as the inputs, and send their values to the two LEDs. In addition to that, I set the three-color LEDs to constant values:

------------------------------------------------------------------------------

process(clk)
begin
    if (rising_edge(clk)) then
        led <= button;
    end if;
 end process;
 

led_r_n <= '1';
led_g_n <= '0';
led_b_n <= '1';

------------------------------------------------------------------------------

I created both .bit and .mcs files from the code. I used Vivado hardware manager to download to the FPGA/FLASH.

After I downloaded the .bit file to FPGA, the DONE and the BLUE LEDs were on. Pushing the buttons doesn't make any change to the LEDs.

After I downloaded the .mcs file to FLASH, the DONE LED was on after the first step and remained lit. No other LEDs were on. Pushing the buttons doesn't make any change to the LEDs. I power-cycled the board, and all the LEDs were off.

Can someone tell me what I could have done wrong? Thanks.

[xc6lx45]

Is it possible that your clock is not there (e.g. not connected to the clock pin)?

I would try a combinational assignment, simply route the button to the LED without clock-driven process.

My VHDL spell checker is still asleep maybe someone else will spots something obvious in the code.

[gfellio]

On 11/17/2018 at 3:50 AM, xc6lx45 said:

Is it possible that your clock is not there (e.g. not connected to the clock pin)?

I would try a combinational assignment, simply route the button to the LED without clock-driven process.

My VHDL spell checker is still asleep maybe someone else will spots something obvious in the code.

I'm using the 12MHz system clock. Maybe it's not working? I'll grab a scope and check it out. Do you know if digilent provides files decribing the signals on the PCB?

 

I set the output to the RGB LEDs to constant which drives Green on. But it doesn't.

 

[xc6lx45]

Hi,

the schematic is here. Double-check your constraints file: GCLK should be pin L17 (sheet 3):

https://reference.digilentinc.com/_media/reference/programmable-logic/cmod-a7/cmod_a7_sch.pdf

You don't need to write to flash: a bitstream .bit file can be uploaded directly to the FPGA. Much faster