Advertisement
; ,:;';-;,:-: 8,);1,\
,IYOJriJ. ';": 1
f
ni. 'rJ
'oJ13 ,~:~ifk)
;\:1:;;·-:
:j
';r!j nxP? .;';:Jr!'(;lRAM
~"
'"h'''''
- -
"-'i".~~)~, _'~"~'~"'_'_'~"X70~'_:""~"'-',i!~'~"_"\_'_-~"~"'v'li'
-0;'
'-:ROM
J"i:ii.;'_)1rij
Qr\8 :-l;;T ..
ii;'~:;
04;'\ -")fi!
:,:;r·!j);-,~;:r: \('-~
l),o.l'i!;,t;-ic,i
~!
1,;jr(tl,ighByte)
r\Y1
n::;ill
_J;1l
:1')
-3. '/],-
,;!
,\,I
;-)rii
"~d:-rJ;,)b:-'i
'J:
j~)GU
,Ii:-,
,-"i;~: l~J'~
'-' i ,
II
' } b
:{l nniU;" fir nJ
:n-,"--;:c':;~ ~;'::::'::::';
' : >1
.'F'
jnt:; 'nol:"h'0~'~
. ...,.""--
"; ' : ,
~:~~:~; ;~~~,:;~,:;.~ ~o~~~;~;;~:,I,'.;:,;;,·;:;,~~£:'. ::);~~iM
;:,., , __ '
.';")
;-~_;'iIJ~
)-!~ R~M
.:'
','i)~
,
r,
,!j':.ji'
,viJ
iiJd FJ';-.r'. ni.s,-,i
::Jf:;-
'-IQ
_:::'!:Jl'd;_'
!,l,
,',-):;;:I;:J '.
i
,CO)
lFigt.irE!'2-g-~JD.ata
-bus
Dp-er~tioh,;
L' '
-r)
'!lpV>'Byte)
~}-'-i~!;:"; ,~;I',V
,-.,,,
'j:>}:-'-1
::-i:
-','J;
iljc,fTl
,:"it
'1--:'
c!-)-j:')
r")
~Z-2l6
..
3i/'D~f~ 'e:b:nV~'rsidH~circuit'~;:U
' j
II))
-'[-;;-'1,""
Fig,2-10 shows the concept of the data conversion circuit'c6ris-iSling
of the SC4751, and Fig,2
i
1)1,{,shQ~~_ ~:t~ll]ipg~~,ph'?rt.rela!_~ct
tQ
_.t~e
circuit
0
eration for an 8-llif
manic
·.J'--~rJliO"device:--'
_'J,
.~.
'I..'
-' "
--,
'.lT~~J~~t~hbriljJt~f6~~gi~b~urtiM~_rt~:t6·%p~r~te ~h~~lthe
C?ti
d6~e's~-es
an odd number word
~,a,t~,of,:~.~~,g~~ir'~~~jce_:~"l
;:
i
-~:,),~:;~"':~'1
1 ) :';,'
"Yt1~9" th~ ·l?P~?~1
.
r~fqg,~f~e:~:~h·.~a_~c"e~$s
J]
~r:i;8~pjt:-d,~viq~,
the
~~I~;;i,~, ~ep¥~~edS~t9"_ t,~f)~r~~Ef~ ,dJ~~~;'~v.11.n~n~~-njg:~'r:p~~,~np
odd
rllimb'ei(byte~ B~da(i~je
-tiie- CPU'
i~:
in'
i' - dr
re,ady' stat¢:'u:ritil
the
end
of the second cycle, it
operq!e§,a~,if,m~~,e_two,~~c)~(W~' j~-O~,e:I!¢YCI~.
~'-.J~,),
"_"JI __ ' ",,-,
'~".I
.. , .. ,,,)11..
",L~,
•
;
)'1IJ~{,~nci"J~Ic(r~;ad"trdrrtJa';
!;a-bli
id~vit:Erih~b~;~w
3d3ojt
'i1
i
(1) At
th~ 'e~~ri
'riuRurer
ii
bY,i1
:r~kiF
.:.!6ie:;(first
h
~I~r,~'~lafa-: r~c
. .
i~ived
'~','
'f'r_-r']
'-~~"'~"""I"'-'-)---
,-,-,,9Y. , ,\
,---,,,y'YJ'--
'~"-"'I'
.
d~_"
JrtJiifbus.
XOtr..:.::t-aJ~' ia~cn~djii
tHs'-SC475L,.''-',
11,) , ,-"
.i:(2r:11(t)'ri~ ,~~~~~{,mb~t~~~ ~~~~: f~~j~ ~(~~q8.~:6Y,t,~~~'~~at~i~beived
" ' , -, "from' bus "XOO":';'Tare
:sent'
onto b(]s"JSOe~15"an'd~",atJthe same
,1:;
"tTIfle-/'t"n~ ~Q&i1i~§iErdiii~JMCfMd%
tf,lSC4151-are,'se'nt throu h
::,t
,·~tGs:xb6\:;.;7.
:'h":)-:.-,:?,,:-,,
-~r,)
:);}
;".!i~~~'
:"::'
"';:~1;~':
' : ,
';j;~
9
:.~3) An_~'~ 11re)-t,~WI.~-gOjK~~fterd,;~~t~ JW~~~~,h'
(0,
b~i _~'~·~~~D~;-j~,
the
." CPU
erminate::d:lccessin'g:"'"
.-' "', '''-'-- , .. , ,,'
.,
.
,:~
- i
~
-
1,
-J i)' , ;
2.0dd word write to an a-bit device
throl,lg~ l;nt~)'Xp,O,",,!?:
-j(HAUhe ,,?,,,en
,nu!T:!I;l,!9Lbyt~ write"~gy;cle:,-(fiE§t: ~YGfe);_ !=I~ta,;,on
bus
LOO-7 are sent through XOO-7 to
writ~;j'
,,":)
1
~-) J'_i''-}-r.',-,
(2) At the odd number byte write cycle (second cycle), data on bus
X08-15 are sent through XOO-7 to write.
3.Even word read from an a-bit device through bus SOO-7
(1) At the even number byte read cycle (first cycle), data received
from bus SOO-7 are sent onto LDO-7 and internally latched.
(2) At the odd number byte read cycle (second cycle), data received
from bus SOO-7 are sent onto bus X08-15 via the swap gate
and, at the same time, the even byte data latched in the SC4751
are sent through bus LOO-7.
(3) After receiving the word data, the CPU terminates accessing.
4.0dd word write to an a-bit device through bus SOO-7
(1) At the even number byte write cycle (first cycle), data on bus
LDO-7 are sent through SOO-7 to write.
(2) At the odd number byte write cycle (second cycle), data on bus
X08-1S are sent to SOO-7 via the high gate and swap gate to
write.
1
;\),11 ::
j, \() T
iii
1
1
Iii
II:
II~
- - 1s118yte
- - - - 2nd 18Vle
CONTRLOFF
v- '-AO
Figure 2-10. Word read
~peration
for'
e~erlial
8 bit
devi~es
PRO ClK
TI
I
TS
I
TC
I
TC
I
T<f
I
TC J TC
I
TC
I
TC
1
TC -( TC J TC
!
TC
Ii
TI
I
SYSClK
I
_
,_
~
iIDiWR:----.
EVEN ADDRESS!
r--:-"J ~ ___
ODD ADDRESS
I
r - -
ARDY
-----.I
DATA
C O N \ ( - - '
ARDlf
EN:~
END
CYCLE'
CONTOFfi
AO
,~
DATA CONY:ERSION:
"I
I
-~ --
__ : __ ,
r--
Lf..J;
L...--l
--
'--,
~i
2>10
Hide quick links:
Advertisement
