counters2020/09/16 · •up/down signed nbit counter (default 8 bit) counters add 1 select + or -...
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![Page 1: Counters2020/09/16 · •up/down signed nbit counter (default 8 bit) Counters add 1 select + or - subtract 1 cnt & 1 → a bcde fgh1 1fd → + 1 1111 1101 n opqr stuv cnt - 1 subtract](https://reader035.vdocuments.net/reader035/viewer/2022071223/607ee3db109a452dd45268a1/html5/thumbnails/1.jpg)
Counters
Last updated 9/16/20
![Page 2: Counters2020/09/16 · •up/down signed nbit counter (default 8 bit) Counters add 1 select + or - subtract 1 cnt & 1 → a bcde fgh1 1fd → + 1 1111 1101 n opqr stuv cnt - 1 subtract](https://reader035.vdocuments.net/reader035/viewer/2022071223/607ee3db109a452dd45268a1/html5/thumbnails/2.jpg)
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Counters
These slides review the design for several types of counters
Upon completion: You should be able to design various types of counters
(up/dn/signed/unsigned/mod)
![Page 3: Counters2020/09/16 · •up/down signed nbit counter (default 8 bit) Counters add 1 select + or - subtract 1 cnt & 1 → a bcde fgh1 1fd → + 1 1111 1101 n opqr stuv cnt - 1 subtract](https://reader035.vdocuments.net/reader035/viewer/2022071223/607ee3db109a452dd45268a1/html5/thumbnails/3.jpg)
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Counters
• Up Counter
• Count in binary• 0000 → 0001 → 0010 → 0011 → 0100 … 1111 → 0000 …
b0 b1 b2 bn-1
D Q
QB
RSTB
D Q
QB
RSTB
D Q
QB
RSTB
D Q
QB
RSTB
clk_in
rstb
What’s wrong with this solution
![Page 4: Counters2020/09/16 · •up/down signed nbit counter (default 8 bit) Counters add 1 select + or - subtract 1 cnt & 1 → a bcde fgh1 1fd → + 1 1111 1101 n opqr stuv cnt - 1 subtract](https://reader035.vdocuments.net/reader035/viewer/2022071223/607ee3db109a452dd45268a1/html5/thumbnails/4.jpg)
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• Counter - n bit - unsigned
Counters
why?2 - reasons
cast
![Page 5: Counters2020/09/16 · •up/down signed nbit counter (default 8 bit) Counters add 1 select + or - subtract 1 cnt & 1 → a bcde fgh1 1fd → + 1 1111 1101 n opqr stuv cnt - 1 subtract](https://reader035.vdocuments.net/reader035/viewer/2022071223/607ee3db109a452dd45268a1/html5/thumbnails/5.jpg)
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Counters
• Counter - n bit – unsigned – (default)
adds 14 bits, hex 1
4 FF’s
adder logic
![Page 6: Counters2020/09/16 · •up/down signed nbit counter (default 8 bit) Counters add 1 select + or - subtract 1 cnt & 1 → a bcde fgh1 1fd → + 1 1111 1101 n opqr stuv cnt - 1 subtract](https://reader035.vdocuments.net/reader035/viewer/2022071223/607ee3db109a452dd45268a1/html5/thumbnails/6.jpg)
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Counters
• Counter - n bit – unsigned (6 bit version)
![Page 7: Counters2020/09/16 · •up/down signed nbit counter (default 8 bit) Counters add 1 select + or - subtract 1 cnt & 1 → a bcde fgh1 1fd → + 1 1111 1101 n opqr stuv cnt - 1 subtract](https://reader035.vdocuments.net/reader035/viewer/2022071223/607ee3db109a452dd45268a1/html5/thumbnails/7.jpg)
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Counters
• Counter - n bit – unsigned (6 bit version)
reset counting
wrap
![Page 8: Counters2020/09/16 · •up/down signed nbit counter (default 8 bit) Counters add 1 select + or - subtract 1 cnt & 1 → a bcde fgh1 1fd → + 1 1111 1101 n opqr stuv cnt - 1 subtract](https://reader035.vdocuments.net/reader035/viewer/2022071223/607ee3db109a452dd45268a1/html5/thumbnails/8.jpg)
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Counters
Mod counter
![Page 9: Counters2020/09/16 · •up/down signed nbit counter (default 8 bit) Counters add 1 select + or - subtract 1 cnt & 1 → a bcde fgh1 1fd → + 1 1111 1101 n opqr stuv cnt - 1 subtract](https://reader035.vdocuments.net/reader035/viewer/2022071223/607ee3db109a452dd45268a1/html5/thumbnails/9.jpg)
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• Mod 11 counter
Counters
![Page 10: Counters2020/09/16 · •up/down signed nbit counter (default 8 bit) Counters add 1 select + or - subtract 1 cnt & 1 → a bcde fgh1 1fd → + 1 1111 1101 n opqr stuv cnt - 1 subtract](https://reader035.vdocuments.net/reader035/viewer/2022071223/607ee3db109a452dd45268a1/html5/thumbnails/10.jpg)
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Counters
• Mod 11 counter
control selection ofcnt+1 or 0
add 1
check for < 0cnt – 10 (4bit, hex a)
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• Mod 11 counter
Counters
counting mod11 wrapreset
![Page 12: Counters2020/09/16 · •up/down signed nbit counter (default 8 bit) Counters add 1 select + or - subtract 1 cnt & 1 → a bcde fgh1 1fd → + 1 1111 1101 n opqr stuv cnt - 1 subtract](https://reader035.vdocuments.net/reader035/viewer/2022071223/607ee3db109a452dd45268a1/html5/thumbnails/12.jpg)
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Counters
Up/Down counter
![Page 13: Counters2020/09/16 · •up/down signed nbit counter (default 8 bit) Counters add 1 select + or - subtract 1 cnt & 1 → a bcde fgh1 1fd → + 1 1111 1101 n opqr stuv cnt - 1 subtract](https://reader035.vdocuments.net/reader035/viewer/2022071223/607ee3db109a452dd45268a1/html5/thumbnails/13.jpg)
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• up/down signed nbit counter
Counters
![Page 14: Counters2020/09/16 · •up/down signed nbit counter (default 8 bit) Counters add 1 select + or - subtract 1 cnt & 1 → a bcde fgh1 1fd → + 1 1111 1101 n opqr stuv cnt - 1 subtract](https://reader035.vdocuments.net/reader035/viewer/2022071223/607ee3db109a452dd45268a1/html5/thumbnails/14.jpg)
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• up/down signed nbit counter (default 8 bit)
Counters
add 1 select + or -
subtract 1cnt & 1 → a bcde fgh11fd → + 1 1111 1101
n opqr stuv
cnt - 1
subtract 1Shift and concatenate 1 2x + 1Add -3 + -3
2x – 2
Only select upper bits → /2 x - 1
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• up/down signed nbit counter (6 bit test)
Counters
![Page 16: Counters2020/09/16 · •up/down signed nbit counter (default 8 bit) Counters add 1 select + or - subtract 1 cnt & 1 → a bcde fgh1 1fd → + 1 1111 1101 n opqr stuv cnt - 1 subtract](https://reader035.vdocuments.net/reader035/viewer/2022071223/607ee3db109a452dd45268a1/html5/thumbnails/16.jpg)
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• up/down signed nbit counter (6 bit version)
Counters
reset counting up
transition to negative
counting down
transition to positive