Upload
adele-watts
View
214
Download
1
Embed Size (px)
Citation preview
Logic DesignCS221
1st Term 2009-2010
CountersCounters
Cairo University
Faculty of Computers and Information
24/10/2009 cs221 – sherif khattab 2
Administrivia homework #4 due next lecture meeting with mentor TAs on wednesday : الخميس الصغيرة م٥ص-٩المشروعات
24/10/2009 cs221 – sherif khattab 3
serial adder
24/10/2009 cs221 – sherif khattab 4
serial adder with JK flip-flop
24/10/2009 cs221 – sherif khattab 5
serial adder with JK flip-flop
24/10/2009 cs221 – sherif khattab 6
universal shift register
24/10/2009 cs221 – sherif khattab 7
universal shift register
graphic symbol
24/10/2009 cs221 – sherif khattab 8
universal shift register
function table
24/10/2009 cs221 – sherif khattab 9
binary counters
• an n-bit binary counter consists of n flip-flops and can count in binary from 0 through 2n - 1
• Binary counters use flip-flops in complementing mode, such as:
– T flip-flop with T=1
– JK flip-flop with J=K=1
– D flip-flop with D=Q'
24/10/2009 cs221 – sherif khattab 10
ripple counters
• A0 is complemented every clock cycle
• A1: every time A0 goes from 1 to 0 (negative edge)
• A2: every time A1 goes from 1 to 0 (negative edge)
24/10/2009 cs221 – sherif khattab 11
binary ripple counter
24/10/2009 cs221 – sherif khattab 12
synchronous counters
All flip-flops have a common clock