Lecture Notes for ENEE244, Fall 1998. October 7, 1998. Today we'll try and cover
the following topics: • Half adder. • Subtractor (full and half). • Decimal addition ...
!#"#$#%'&(&*),+!+!. /102436587:9=@??A BDC8EGFIHKJ6LNMPOQORTSUHVFWXEVYZC\[LZS]RT^XL _`CaOQObC\J]cbWXdeRTCafXcQYZgih jlk FOm_FNEXEXLZS jon@pXq RrSTFY(RTCaSes`_ p ObOFNWXE:^XFOQ_Tt jlu LZYZcQvwFNOFEXExcQRTcQCaWys{z| u FExEXLZSTt jl}~ FvfXOQL fXSrC q ObLZvg 'Z
N'# FgUReRrcbvLJ6LEXcbgY p ggrLZEFV_ p ObOFNEXEXLZSiVB^XLw^GFNOQ_FNEXEXLZScbg[aLiSHygrcQvcQOFSL ~ YZLifxR Rr^GFNR]cmR]EXC@Lig]WXCR]^GFI[aLeFYIFSSHcQWB^XL q ObC8YwExcFdaSrFvcQgZh a
f
Half Adder
b
cout
B^xL^GFOQ_FEXEXLiSWXLZLiEXg RTCFNEXERJ6CcQWXf p RrgRTCdaLiRr^XLZS FNWXE#fXSrC8E p YiLFKg p vFWxEF YZFSrSUH q cmRIB^XL RTS p RT^VRF q ObL cQgRT^XLiWh F q ¡ £¢¡¤ _ ¥ ¥ ¥ ¥ ¥ ¦ ¥ ¦ ¦ ¥ ¥ ¦ ¦ ¦ ¦ ¥ ¦
§¨C p gr^XC p ObESLZYiCadaWXcQ©ZL ¡ £¢¡¤ Fg ( £¢¡¤ª«¬ FWXE Rr^XL!g p v®C p RTf p RI¯4_°¯4Fg± ª«²³¬ ´µLYIFWVRT^xLZW¶EXSTFIJ·Rr^XL^GFOm_¸°FEXExLZSYicbSrY p cQRZh ¹ a
f
b
º»
cout
V¼ ½ Io'# ¾ ¿#ÀIÁ ÂWRT^XL>OFgURObLiYiR p SrL,J6LRTFObNLZEwF q C p R^XC\J³RrC!cbvfXObLivLiW1R6F_ p ObOÃFExEXLZSiÄ>C\JÅRT^GFNR JL^GFI[aLKRr^XL^GFOm_,FEXEXLiS p WXExLZSC p S q LiOQRTgeJ6LYZFWFYiR p FOQOQH qXp cQObEÆF _ p ObOFEXEXLiS _`SCavÇFfGFcbS'C_,^GFOQ_,FNEXEXLZSgFWXECaWXLKFEXEXcmRTcbCWGFO6ÈÉÊd1FNRrLyB^XLYZcQSrY p cQR!OQC@C8g OQcbNLh a b
Ì
c in
Ë ÍÌ
Half c Adder s
Ë ÌÍ
Half Adder
Ì
c s
Í
c out sum
Full Adder
Î ½#Ï Ð !Ñ ÐÒ Á ´µLYIFW qXp ObE q CRT^V_ p ObOFNWXE:^XFOQ_g pXq RrSTFY(RTCaSgZÓÔ_ p OQOg pXq RTSTFNYiRTCS>g pXq RTSrFYiRrg>RJC W p v q LiSrgZ¯FFNWXE q ¯ÕRrCadaLiRr^XLZSJ]cmRT^#F q CaSSrC\JcbWRTCwfXSrC8E p YiL!RT^XLEXcmÖÕLiSrLiWXYZLFWxE F q CaSSrC\JÊC p RTf p RIµÓ×^GFOm_]g pXq RrSTFY(RTCaSg pXq RrSTFY(RTgRJ6CW p v q LZSgZ¯¨F#FWXE q ¯¨FWxE fxSrC8E p YZLig,Rr^XLEXcQÖ4LZSLZWXYiLFWXE:F q CaSSrC\J·C p RTf p RIB^XL q ObC8YwEXcbFdaSrFvg6ObC8CaOQcbNLh Ø
a
Ù
b out
b
Ú
Full Subtractor
a
b in
b out
b
Û
Half Subtractor
d
d
Ü Ý ÞÞßXÝ à>áxâGãäÕáXå¨â BDC p WXExLZSrgURFWxEJ]^XFNRRr^XcbgYicbSY p cmRcQgg p fXf4CgrLZE#RrCEXCKObL(RIMæg>RTFLFwYiObCagL!ObC8CaVFNR FNW¶L ~ FvfxObL C_ q cbWGFNSHKg pXq RrSTFY(RTcbCWh b out = 1
b out = 1
-
02 0010 1001 1001
b in = 0
B^xL q CaSrSCçJcbWÅRTCRT^XLèGSrgURg pXq RTSrFYiRrcbCaWécbg¶©ZLiSrC q LiYIF p gLêWXCNRT^XcQWXdl^XFg q LZLiW q CaSSrC\J6LiE:HLiRI6B^XLZW JLWXLZLiE RTCg pXq RTSTFNYiR ¦ _`SCav ¥ ¨´êLYIFNWMæR>EXCRT^GFëRCaW¶C p S C\J]WìgrCJ6LVWXLiLZEìRTC q CSrSrC\JíCaWXL_`SrCvÇRT^xL¶WxL ~ RwW p v q LiSF q C\[L p g°¸RT^GFëRgLiRrg C p RRrC ¦ wÄ,C\JJLYZFWµg pXq RrSTFY(R¸>J6L q CSrSrC\JLZE_`SrCav®RT^XLWXL ~ Re^XcQda^XLZS qExcbCadaScmSrRC\Jî grCRT^XFNR,dacQ[LZg p g,F!RTCRTFOC_ Ø RrCJ6CaSwJ]cQRr^,s Ø ¸ ¦ t ª ¦ gCC p S]E¶cQg ¦ B^xL!WXL R g RrSTFY(RTcbCWJFW1RrgRTCKg RrSTFY(R ¥ _`SrCav ¦ É,LivLiv LZSZ¯ÃRT^XC da^¯ÃRT^GFNR JL^GFNE~ F q CapXSrq SC\Jï_`SrCav q Li_`CaSLB^XpXFNRq vLIFWxg q CaSrSCçJcQW'cQg ¦ n Cq èGSgRRTCKRT^xL'_ p ObOF q C p R ¬ £¢¡¤ ÿLiRIMæg,ObC8CawFëR,FFSWGF p d^:vFfh ab
00
01
11
10
0
0
1
0
0
1
1
1
1
0
b in
¬ £¢¡¤ª « ¬l« ¬Tôöõ!쬡¬ôþõ ª « ¬ s « a²ò¬ t ¬ôþõ |6CvfGFNSrLRT^XFNR]RTCJ]^GFNR]JL^XFE¶_`CS ( £¢¡¤ cbWRT^xL_ p ObOÿFExEXLZSih ( £¢¡¤ª·«"¬ s «²o¬ t ¡ôöõ nCN_CeYZHaC C p SrgrYILNF¯ÕWvdaFLiR6LiFg_ fÃp LZObOGS_`g LipxYiq RRTgrSrLZFWxYigrRrLCaS¨grcQ_`WXSCaYZvLHaFC _ p YIObOFFWEXg ExLZS Rrq STFHY(YiRCaRvJfxCObLZW vv LZW1RrLicbWXSrgdFxH:BYZC^xvcbgZ¸ ¯ p p pXq p q q fxObLZvLZW1RrcbWXdCaWxLCN_À%$ ! À%'À Ð)( ##À Ð À Ò+* ,.-0/ # 1 ÿ L(RIMæggTFIHwJLJ6FW1RRTC qXp cbObEwF!YZcQSrY p cQR¨RT^GFNR6J]cbObOÃFExEKRJ6CEXLiYZcbvFOÃEXcbdcQRTg¨cbWKz| u _`CSrvRTCadaL(RT^XLiSJ]cQRr^FKYIFSSH cbWXf p RI¯fXSC@E p YZcQWXdwRT^xLZcbSg p vFWXEyFKYIFSSH:C p Rrf p RI k cQC\RTJgi¯ÕFNvwWXFEW1HFwYIcQWXFNf SrSp H¶Rrg'cQWEXC¶BJ6^XLKcQg^XvF\[FL LigB2x^X LiSrLC\JFSLF RC JC#RzC | RTu f W RTgp v ´êq LiLeSrgZ^G¯FILI[aFLY^êCaWxJ]LecmRT_`^C S q k q p p p p q cQR]C p Rrf p R,FWxE¶Rr^XLYIFSSHC p R,_`CS]FRrCRFNOC_3@B^XL q ObC8YwEXcbFdaSrFvOQC@CagOQcbNLh 3
5 5 5 5
4 4
y3 y2 y1 y0
x3 x2 x1 x0
6
Decimal Digit Adder c out
(DDA)
6
c in
´µL YZC p ObEVvFLF72 q cQR6RF q OQL FWXEVfXSC@YiLZLiE¶_`SCavíRr^XLZSL p grcbWxd!RT^XLgTFNvL fXSC@YiLZgg JLMð[aL q LiLZW p grcQWXdX´µLYZC p OQE¶FObgCExCRr^XLFEXEXcmRTcbCWKcbW¶F q cbWXFSHK_`CSrv¶ ´Å^XFNR F q C p R>C p S,C p Rrf p R Âú_Rr^XL'g p v cbg,daSrLZFNRTLiS,Rr^GFW ¦\¥ J6L'WXLZLiERTCwg pXq RrSTFY(R ¦I¥ _`SCavcmRFWXEgrL(RRT^XLYIFNSrSHC p R RTC ¦ z p R^XC\JîYIFNWyJLg pXq RrSTFY(R ¦\¥ ´µLZOQO£¯ JL'LicQRr^XLZS qXp cQObE:FYZcQSrY p cQR]RTCg pXq RTSTFNYiR ¦I¥ CaS,CaWXLRTCwFEXE:¸ ¦\¥ z p R>J]^GFëRcbg¸ ¦I¥ s 9¦ 8 ¸ ¦\¥ t ª 8 ´êLYZC p ObERT^xLZSrL(_`CaSrLFExE 8 cbWxgRTLZFE ´µLMæObOÕYZCaW1RTcQW p L RT^XLz| u FEXEXLiS,cQWRT^XLWXL ~ R,OQLZYiR p SrLNQm
8