assigned a pin to ground

[Altera_Forum]

Hi everyone,  

I have a max10 FPGA and I want to assigned a pin to the gnd Because my circuit is like this: output pin(3.3V ) LED power supplied(3.3V) so If I want to light up my LED, I should have an output pin=0V. I've try some VHDL code, it seems it doesn't work  library ieee; use ieee.std_logic_1164.all;     ENTITY et IS PORT(   s : out std_logic ); END et ;   ARCHITECTURE data_flow OF et IS BEGIN s<= '0';   END data_flow;  I've also tried null instead of 0. But it still doesn't work. is it because I don't have IN std_logic  thank you in advance

[Altera_Forum]

Did you assign s port to the correct device pin?

[Altera_Forum]

thank you for ur replying. Yes I did and i'm sure about that

[Altera_Forum]

--- Quote Start ---  Because my circuit is like this: output pin(3.3V ) LED power supplied(3.3V) so If I want to light up my LED, I should have an output pin=0V. I've try some VHDL code, it seems it doesn't work  --- Quote End ---  What is the value of your current limiting resistor? Did you put a scope or a meter to measure the output pin? Kevin Jennings

[Altera_Forum]

--- Quote Start ---  I've also tried null instead of 0.  --- Quote End ---  Null would be incorrect, '0' is correct.   --- Quote Start ---  But it still doesn't work. is it because I don't have IN std_logic  --- Quote End ---  No Kevin Jennings

[Altera_Forum]

The pins can source and drain the required current? I would reccommend using a ground pin. I think there must be a couple of those.

[Altera_Forum]

Thank you for your replying, 

I couldn't really measure the current, now. Because I work in a starting project. But it was an experimented engineer, who develop that board. So I think he should think about that. I thought it may be have problem of compatibility of USB blaster II, which is not compatible with Altera max10 or the frequency of Jtag, 6MHz instead of 24MHz, but I don't know how to change that frequency

[Altera_Forum]

Ok, thank you

[Altera_Forum]

--- Quote Start ---  What is the value of your current limiting resistor? Did you put a scope or a meter to measure the output pin? Kevin Jennings  --- Quote End ---     Thank you for your replying, I couldn't really measure the current, now. Because I work in a starting project. But it was an experimented engineer, who develop that board. So I think he should think about that. I thought it may be have problem of compatibility of USB blaster II, which is not compatible with Altera max10 or the frequency of Jtag, 6MHz instead of 24MHz, but I don't know how to change that frequency

[Altera_Forum]

--- Quote Start ---  The pins can source and drain the required current? I would reccommend using a ground pin. I think there must be a couple of those.  --- Quote End ---    Thank you for replying, I couldn't use a ground pin. Because I have to manage light up or light down the LED. Could I just connect the ground directly to an output in schematic, does it work?

[Altera_Forum]

well, you need to complete the circuit, so it should work, assuming the output can drive enough current.