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5. DESCRIPTION OF THE CIRCUIT OPERATION
1. ARM 7500 part
T h e c ircu it is d ivide d in to d ig ita l a n d a n a lo gu e in p ut/o u tp u t p arts arou n d the A R M 7 50 0 p art.
T w o a d dre sse s an d tw o d ata b us es a re b a sica lly serve d from th e A R M 7 5 00 p a rt.
R A (D R A M R O W /C O L U M N M U L T IP LE X E D A D D R E S S E S ) u ses 1 2 b its.
L A (L A T C H E D A D D R E S S E S ) u se s 2 9 b its.
D (M A IN D A T A B U S ) u se s 3 2 b its.
B D (M A IN E X T E R N A L B U S ) u se s 1 6 b its.
R A a n d D a re co n n e cted to th e D R A M (th e ca pa city is 8 M b yte), th e m a in m em o ry,
in th e S IM M m o d u le , a n d are u se d w h e n th e ac tu a l p ro g ra m is op e ra te d .
2. PROM part
D a n d L A a re co nn e cte d to the P R O M (th e ca pa city is 4 M b it).
W h e n the p o w e r is tu rn e d o n , the syste m re ad s th e in itia l pro gra m co d e s set in th e P R O M
an d lo a ds th e m o n to th e m e m ory.
T h e re is a s m a ll W E B B R O W S E R fo r e m e rge n cy u se in th e P R O M .
T h is ca n be u se d if th e re are an y p ro b le m s in th e W E B B R O W S E R .
T h e R O M c an b e loa d e d b y o p e ra tin g th e p o w e r S W a n d th e A /S S W .
(T u rn th e p o w e r S W o n w h ile p re ssin g the A /S S W , th en tu rn th e A /S S W o ff in 2 se c.)
3. FLASH MEM ORY part
B D and LA are connected to FLA S H M E M O R Y (the capacity is 1 M byte to 4 M bit m em ories- [1 byte = 8 bit]),
w h ich p e rfo rm s th e sa m e fu nc tion a s a h a rd d isc in a P C .
T h e m a in pro gra m , W E B B R O W S E R , is lo a de d , a nd th e IN T E R N E T S E T T O P B O X o pe rate s.
4. RECEIVER CIRCUIT part
A P S /2 -typ e ke yb oa rd a n d a P S /2 -typ e m o u se u se d for P C s a re p ro vid e d fro m the A R M 7 50 0 .
T h e se c an b e c on n e cted a s n orm a l-typ e w ire d ke yb oa rds a n d m o u se s or ca n b e us ed a s
w ire le ss-typ e ac ce sso rie s th ro u gh th e rec eive r circuit c om p os ed o f w ireles s re ce ive r d e vice s,
89 C 2 05 1 an d 9 7C 5 2 .
5. PRINTER OUTPUT part
8 b it d a ta is su p p lie d to th e p rin te r p o rt fro m B D thro ug h 7 4H C 3 7 7 fo r p rin ting .
T h e p rin te r c on tro l sign a ls a re su p p lie d th ro u g h th e 8 b it W ID E IO P O R T .
6. IM AGE OUTPUT part
V G A sig na ls a re p ro vide d to d isp la y im a g es d ire ctly to th e P C m o n ito r fro m th e A R M 75 0 0 .
T h e c om p o site v id eo a n d S -V H S (Y , C ) sig na ls a re p ro vide d so th a t the sig n a ls ca n b e d isp la ye d o n
the C R T u sin g th e C H 7 00 1 A N T S C E N C O D E R .
H o riz on ta l/ve rtica l p o sitio n ch an g e : U P (2 6 ), D O W N (2 7 ), LE F T (2 8 ), R IG H T (2 9 )
N T S C /P A L se le ctio n : N T S C *P A L (30 )
F lic ke r filte rin g : M S 0 (1 1 ), M S 1 (1 2 )
Summary of Contents for DSN-300A
Page 5: ...4 3 BLOCK DIAGRAM...
Page 37: ...36 10 EXPLODED VIEW 10 1 DSN 300A...
Page 39: ...38 10 2 MODEL DSN 300S...
Page 42: ...41 11 SCHEMATIC DIAGRAM...
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