Sharp PC-7200 Service Manual page 75

xo
MEMW
CRTClK
IL ______
---I
CRTCAS _ _ _ _ _
....J
XO
MEMW
CPMES
CRTClK
IL ______
---l
CAS . I l L _ _ _
CATRAS
CRTCAS _ _ _ _ _ -....l
CPURAS
CPUCAS
DRAM
ADDRESS
CPURAS
X
CPUCAS
XL ___
Jl X
L
_ _
r -_ _ _
~CPU
WRITE DATA
MDO-MD7
~
>----
XACK
Figure 7-9. Video RAM access
by
the CPU in the CRT mode (Write)
L--_ _
IlL_----.J
DRAM
--y
ADDRESS
---11
CPURAS
X\._C:::!P:..:U~RA~S'-.JXL
_ _ _
MDO-MD7
_ _ _
~lli.I;~\\V.L_~
CPU READ DATA
XCACK
Figure 7-10. Video RAM access by the CPU in the CRT mode (Read)
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P C-720D