Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

  • Congratulations derfloh on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!

Glitch problem

Status
Not open for further replies.

mmali69

Technical User
Joined
May 3, 2006
Messages
1
Location
US
Hi All,

I am doing an FPGA Design where most of the VHDL code I am using is a reuse from another device (Designed by some other group who are not around).

In this code(s), there are a lot of signal assignments where the output of a block or even an internal used signal is not clocked. As a result, I am seeing glitches in the simulation using ModelSim tool.

Unfortunately, If I wanted to put these signals in clocked process for example (as a solution to the glitches), the timing where these signals are expected (from other places they are used) is messed up and as a result most of the code(s) don't work probably. Is there any way I can fix this. Fot example, is there anyway I can change below assignments without the need of putting them in a clocked process and hence introducing a delay.

cmp_rls <= STAT_DV and (STAT(0) or STAT(1));
data_end <= '1' when ( (data_byte_en/=(conv_std_logic_vector(0,data_byte_en'length)-1)) and DFIFO_DV='1') else '0';

Thanks in advance.

mmali69
 
My suggestion:

Use "after X ns " in each assignment ?!! (X is watever u want)
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor

Back
Top