Hello,
I am looking for some advice - hopefully i have made a schoolboy error.
I have a problem with an output from a cyclone III starter kit.
I have written a very basic block of code in VHDL to send the clock from the board directly to one of the outputs:
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
ENTITY hsmc_test IS
PORT ( input : IN STD_LOGIC;
hsmc : OUT STD_LOGIC);
END hsmc_test;
ARCHITECTURE behav OF hsmc_test IS
BEGIN
hsmc <= input;
END behav; In the pin planner i have tried several settings for the IO standard inlcuding:
3.0V LVCMOS, 3.0V LV TTL etc.
The problem is that the output is only being driven to about 700mV peak to peak.
I am using Quartus II version 8.0.
I origionally had a more complicated VHDL function which was working in simulation but not in hardware.
The external hardware i am trying to drive requires the clock from the FPGA to have a minimum 2.5V for logic high, therefore i assume that this is the reason i had a problem.
I would be grateful for any assistance. Thanks in advance.
Regards
Ade
