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Quartus synthesis constrain

Altera_Forum
Honored Contributor II
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Hi, 

 

In my project, the following code was to delay the data, I want to use the logic elements to implement in fpga, but the Quartus automatically use altshift_taps to implement which will cost one M9K. 

 

Does there any constrains to constrain it using logic elements? 

 

 

Thanks, 

 

FPGA: EP3C40 

QUARTUS II 8.1 

 

 

-- 

-- delay the input data 

-- 

pes_ua_array(0) <= pes_ua; 

pes_ua_fs_array(0) <= pes_fs_ua; 

 

pes_ua_delay:  

for i in 1 to 13 generate 

 

process(rst,clk) 

begin 

if (rst = '1') then 

pes_ua_array(i) <= (others=>'0'); 

pes_ua_fs_array(i) <= '0'; 

elsif (clk'event and clk = '1') then 

if (pes_v_ua = '1') then 

pes_ua_array(i) <= pes_ua_array(i-1); 

pes_ua_fs_array(i) <= pes_ua_fs_array(i-1); 

end if; 

end if; 

end process; 

 

end generate;
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Altera_Forum
Honored Contributor II
362 Views

Hi, 

 

This might be helpful 

 

http://quartushelp.altera.com/10.0/mergedprojects/hdl/vhdl/vhdl_file_dir_attribute.htm (http://quartushelp.altera.com/10.0/mergedprojects/hdl/vhdl/vhdl_file_dir_attribute.htm

 

As an example it shows the use of the AUTO_SHIFT_REGISTER_RECOGNITION attribute. Which it looks like you'll need to set to OFF 

 

Hope this helps 

 

Vern
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Altera_Forum
Honored Contributor II
362 Views

Hi Vern, 

 

Thank you very much! 

 

Synthesis Attribute is what I need. 

 

Regards, 

 

HXD
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