AM29F002BT-70JC Spansion Inc., AM29F002BT-70JC Datasheet - Page 21

• Manufacturer Part Number: AM29F002BT-70JC
• Description: Flash Memory IC
• Manufacturer: Spansion Inc.

Specifications of AM29F002BT-70JC

• Memory Size: 2Mbit
• Memory Configuration: 256K X 8
• Ic Interface Type: Parallel
• Access Time: 70ns
• Memory Case Style: PLCC
• No. Of Pins: 32
• Operating Temperature Range: 0°C To +70°C
• Termination Type: SMD

DQ6: Togg le Bit I
Tog gle B it I o n D Q6 in dic a te s w h ethe r a n Em b edd ed
P rog ram o r E ras e al gor ithm i s in pro gre s s or c om p lete,
o r w hethe r the d ev ic e ha s e ntere d the E ras e S us p end
m o de. Tog gle Bit I c an b e re ad at any a dd res s , a nd is
v alid afte r th e ri si ng e dge o f the fin al W E # pu ls e in the
c o m m an d s e qu e nc e (p ri or to the pr og ra m or er as e
o pera tion) , an d du rin g th e s ec tor er as e tim e-o ut.
D u r in g an E m b ed d e d P r og ra m o r E r as e a lg o ri th m
o p er a tio n , s u c c e s s i v e r e a d c y c le s to an y a dd r e s s
c au s e D Q6 to tog gle. (T he s y s tem c an us e e ither O E#
o r C E # to c o ntrol the re ad c y c les .) W hen the o pe ration
is c om p lete, D Q 6 s tops togg ling .
A fter an e ra s e c om m a nd s eq u en c e i s w ri tten , i f a l l
s ec tor s s e lec ted for eras in g a re p rotec ted , D Q 6 to ggle s
for ap prox im a te ly 1 00
d a ta. If n ot a ll s e le c te d s e c to r s ar e p r ote c te d , the
E m b ed d ed E ra s e a lg or ith m er as e s the u n pr ote c ted
s e c to r s , a n d i gn o re s th e s e le c te d s ec tor s th at a re
p rotec ted .
T he s y s te m c an us e D Q6 an d D Q 2 tog ethe r to d eter-
m in e w heth er a s e c to r i s ac tiv ely e ras in g or is e ras e-
s us p end ed . W h en th e d evi ce is ac tiv ely er as ing (that is ,
the E m b ed de d Er as e al go rith m i s in p ro gre s s ), D Q6
tog gl es . W h en th e dev i ce e nte rs th e Era s e Su s pe nd
m o de, D Q 6 s to ps tog glin g. H ow ev er, th e s y s te m m us t
a ls o u se D Q 2 to deter m in e w h ic h s ec tor s are er as ing
o r e ras e -s us pe nd ed. Alter na ti ve ly, the s y s te m c an us e
D Q 7 (s ee the s u bs ec tion on
If a p ro gr am a dd re s s fal ls w ithi n a pr ote c ted s e c tor,
D Q 6 tog gle s fo r ap pro xi m ately 2 µs a fte r the pro gra m
c om m and se qu enc e i s w r itte n, th en re tu rn s to r ead ing
a rray data.
D Q 6 als o tog gle s d ur ing the e ras e -s us p en d-p ro gra m
m o d e , a n d s to p s t o g g l i n g o n c e th e E m b e d d e d
P rog ram alg ori th m is c om plete.
T he W r ite O pe ration S ta tu s table s ho w s th e outpu ts for
Tog gle B it I o n D Q6 . R efer to
a lgor ithm , a nd to the Tog gle Bit T i m ing s fi gur e i n
C h ara c ter is tic s ”
D Q 6 figu re s ho w s th e d iffe re nc e s b etw ee n D Q2 a nd
D Q 6 i n gr ap h ic a l fo r m . S e e
p age 1 9.
DQ2: Togg le Bit II
T he “Togg le B it II” on D Q 2, w he n us e d w ith D Q6 , i ndi-
c a tes w he the r a pa r tic u lar s e c tor i s a c tiv ely e ras i ng
(tha t is , the Em bed de d E ras e a lgor ithm is in p rogr es s ),
o r w he th er th at s ec tor is era s e-s u sp en ded . To gg le B it
II is va lid a fter the r is ing e dge o f the fin al W E# p uls e in
the c o m m and se qu enc e.
D Q 2 tog g le s w h en the s y s te m re a ds a t ad d re s s e s
w ith in th os e s e cto rs th at h av e b ee n s ele c te d fo r e ra -
s ur e. (T he s ys tem c a n u se eith er O E# or C E # to co ntro l
for th e tim ing d ia gra m . T h e D Q2 v s .
µ
s , then r eturn s to re adi ng ar ray
“D Q 7: D ata# Pol ling
F igur e 5
“D Q2 : Tog gl e B it II”
fo r the to ggle b it
A m 29 F 002 B /A m 29 F 00 2N B
”).
“ AC
o n
th e re ad c y cl es .) Bu t D Q2 c an not d is tingu is h w hethe r
th e s ec tor is ac tiv e ly e ras i ng o r i s er as e -s us p en de d.
D Q 6 , by c o m pa ris o n, in dic a te s w h ethe r th e dev ic e is
a c ti ve ly era si ng, or is in E ras e Su sp en d, but c an no t d is -
tin gui sh w hi ch s ec tors are s ele cte d for e ras u re. T hu s,
b oth s ta tus b its ar e req uir ed fo r se c to r and m o de in fo r-
m ation . R e fer to
a nd D Q 6.
F igu re 5
for m , a nd th e s ec tio n
a lg o ri thm . S ee al s o the Se e
p ag e 19.” R e fer to the To gg le Bit T im in gs fi gur e fo r th e
to g gl e b it tim i ng di ag ra m . T h e D Q 2 v s . D Q 6 fi gu r e
s h ow s the d iffer enc e s betw ee n D Q 2 a nd D Q6 in gr aph -
i ca l for m .
Reading Toggle Bits DQ6/DQ2
R efe r to
e v e r th e s y s te m i n iti a ll y b eg i n s re a d in g t og g le b it
s tatus , it m us t rea d D Q7 –D Q 0 a t lea s t tw i ce in a ro w to
d eter m ine w he th er a tog gle bit is tog gli ng. Ty pic a lly, a
s y s tem w oul d n ote an d sto re th e va lue o f th e togg le bit
a fte r the firs t re ad . Afte r th e s e co nd re ad, th e s y s tem
w o uld c o m par e th e new v alu e of th e to gg le bit w ith th e
fir st. If the togg le b it is no t to ggl ing, the dev ic e ha s c o m -
p leted the pro gra m or era s e o per ation . T h e s y s tem c a n
r ea d a rra y d ata o n D Q 7 –D Q 0 o n the fo llo w in g re a d
c y c le.
H o w eve r, if afte r th e in iti al two rea d c yc le s , the s y s tem
d e te r m i ne s th a t th e to g gl e bi t is s t il l to g gl in g , th e
s y s te m a ls o n otes w h ethe r the v al ue o f D Q 5 is h ig h
( s ee the c an on D Q 5). If it i s, th e s y ste m s h oul d dete r-
m ine ag ain w h ethe r th e to ggl e bit i s tog glin g, s in c e th e
to ggle b it m ay hav e s topp ed tog glin g jus t a s D Q 5 w ent
h igh . If th e tog gle b it is no lo ng er to ggli ng, th e d ev ic e
h as s uc c e ss full y c om pl eted th e p rog ram o r er as e o pe r-
a tion. If i t is s till tog gli ng, th e d ev ic e d id no t co m pl ete
th e o pera tion s uc c es s fu lly, an d th e s y s te m m u st w r ite
th e res et c om m a nd to re tu rn to re adin g ar ray d ata.
T he re m ai ni n g s c e n a ri o i s tha t the s y s te m i ni tia l ly
d eter m ine s th at th e to gg le bi t is togg ling and D Q5 h as
n ot g on e hig h. T he s y s tem c an c on tin ue to m on ito r th e
to gg le b it a n d D Q5 th ro ug h s uc c e s s iv e re a d c y c les ,
d e te r m in in g the s ta tus as d es c r ib ed i n the p re v io us
p ara gra ph. A lter nativ ely, it c a n c h oos e to p erfor m othe r
s y s tem ta s ks . In th is c a se , the s ys tem m us t s tar t at th e
b eg inn ing of the a lgo rithm w hen it r etur ns to dete rm in e
th e sta tu s o f the o pera tion (top of
DQ5: Exceeded Tim ing Limits
D Q 5 i ndic a te s w hethe r the p ro gram o r era s e tim e h as
e xc e ede d a s pec ifie d in te rn al p uls e c oun t lim it. U nde r
th es e c o ndi tio ns D Q 5 pro duc e s a “ 1.” T h is is a fa ilur e
c o ndi tio n th at ind ic ates th e p rogr am o r e ras e cy c le w as
n ot su c c es s fu lly co m ple ted.
F i gur e 5
s ho w s th e to gg le b it alg o rith m in flo w c h ar t
Table 6
fo r th e fo llow i ng di s cu s s ion . W h en -
“D Q 2: Togg le B it
to c om par e ou tp uts for D Q 2
“ D Q 6: Tog g le B it I”
F ig ure
II” ex p lain s th e
5).
19
on