How about this if condition 1. )If the output of the 74390 reach the NAND4 at the same time bBRA Copyright 1997 Altera Corporation 9/12/97
Copyright © 1997 Altera Corporation 9/12/97 How about this IF condition ? 1.) IF the output of the 74390 reach the NAND4 at the same time
74390 All four dFF clocking by DIFFERENT CLOCK SOURCE ⊥QC OuTPUT ⊥QB 1CLKB iAND 1QB PRMH1QAoureur 1 CLKA ⊥cLR
Copyright © 1997 Altera Corporation 9/12/97 74390 All four DFF clocking by DIFFERENT CLOCK SOURCE
What it course by different Clock Source The DFFs clocking by Four different Clock Source the output of the dFF will come out at different time a The output of 74390 goes to the 7442 at different time will cause Decoding Glitch detail of Combinational Circuit Decoding Glitch, please refer to the Design of Combinational Circuit presentation material a How to solve the problem play around with the trace delay -BAD SOLUTION 2 )change the design from Asynchronous Circuit to Synchronous Circuit -PERFECT SOLUTION ■HoW? Copyright 1997 Altera Corporation 9/12/97
Copyright © 1997 Altera Corporation 9/12/97 What it course by different Clock Source ◼ The DFFs clocking by Four different Clock Source – the output of the DFF will come out at different time ◼ The output of 74390 goes to the 7442 at different time will cause Decoding Glitch – detail of Combinational Circuit Decoding Glitch, please refer to the Design of Combinational Circuit presentation material ◼ How to solve the problem ? – 1.) play around with the trace delay - BAD SOLUTION – 2.) change the design from Asynchronous Circuit to Synchronous Circuit - PERFECT SOLUTION ◼ How ?