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.....
'
---------------------------------------------------------------------------
---------=F~~~
Pin No.
Signal name
InlOut
Description
, ..
~
.
c ·
.
.c, :'
.• -"56_.-._ •..
~WDT1
.. , .•...
Out-·-~,
·fDD write.datacompensation outpulsigna" Active·low-when LAis,high,',_
. .
57..
WEco _.. -.Out
. USed 10 directthe FDDto writedala, Active low when
LAis~high.
. .
'.
,
~ '~sa
- -
.. -
Jiead
q.is:~~lect~d
w.ith,:C!-:,loYi
state_of
this-signEd
when
~_i$-at aJlbw
level. Head· 1, -is seleeted--with-a-.
'-Jaw state ofthis'signaf-w.!ii;mL_A is at a lowJevel.
-
J
_
"
'
___ • _' ..
'FIS
'--Ouf
-
..
.
-
, _59
,
HL
...
60
MEN3
61
MEN2
62
MEN1
63
MENO
64
[VSSj
65
[VDDj
66
DS3
67_
. .
D§g
6?.
-._-
.-
DS1.
DSO
70
STP
71
FR
72
LC
73
DR
74
[VSSJ.
75'
. [VDD]
16 ;, "
.
JLil(
77
RDY
8fr
WI'
81
2S
82
m
83
TKO
84
PS1
.
85
PSO
.
.Out ..
___ WSJii:J.to P!r€1ct
thJ~
FOD
to
,lo.sd:the'_readiWiite
heacnm~the
disk._Actfve low ~hen
LA
is
at
a,low
level.
Out
Oul
Out
Out
G
V
Oul
Out
.
Q~J
.
.-
Out.
Oul
Oul
Out
Out
Number 3 unit drive motor enable, active low when LA is at a high level.
Number 2 unit drive motor enable, active low when LA is at a high
level.
,
Number 1 unit drive motor enable, active low when LA is at a;_high level.
Number 0 unit drive motor enable, active
tow~whijii
L",A;'iS"afa:
higliJtiv.et
'.
.
FDC digilal ground
,],
,
.
Single 5V supply.
All VDD
lines connected 10 +5V.
':.
:
Indicates that the number 3 unit is selected, active low when
LA
iE! at a_ hi9-h. JeveJ.< '
i
J
.ln9icates thatthe numbl;!r 2J,mit i§ $el_E;!pled, ?c,tlv€l.IQw.whfJl1 LA.is
a.t
a l:1igh level. ' .
' - ; :
Indicates that the number 1 unit is selected, active
low~wheh
LA is af:a higtllevel.< :,:-'
.:;
Used to deliver step pulse to move the head to another
cylind~_r,
agtive'IQW>''Ihen.LA i$,at a high j@y.et.
Used 10 resel a lault 01 the FDD, active low when LA is at a high iei/el .. ·
_
Indicates that the read/writs head is on the cylinder position
~:fler
·the 4;3rd 6ylil}c;lei, active iQw whell_ LA
is ata high level.
,.; ..... '
....
'.:,'
,'J.},';
"
Indicates Ihe direction 01 the head in the seek mode. Seeks jowards disk peripher)i with a low state of
this signal and disk center with a high state of this signal when LA
is .at a
low leveE;Seeks towards the
disk periphery with a high state of this signal and disk center with a low state of this signal when LA is
at a high level.
'
· - G .
FDC digital ground
, V'
Single +5V supply. All VDpUnes are connected 10 +5V.
,
,
In
Indicates Ihestart point 01 Irack on the disk.
In
Indicales that the FDD is. ready ..
In
Indicates that-the disk is-write-protected', '
In
Indicates the use of two-sided floppy
disk~
.
In
Indicates Ihallhe FDD is at a lault.
In
Indicales thatthe head is on track O.
Out
Indicates
wiit'a
compensation
inform'a~ion
in'the MFM mode.
Lale il PSO is al alow and PS1 at ahigh .
Out
Early il PSO is at a high and PS1 at
a
low.
" .
NQrmal il PSOjs atalowa_nd PSi al a low!
86
D$Ei
,
]
.
':
QUI
FDDselect signal.
I-~=--+--;-"";;'::;';:--,--+--,-"=:::"--j
#0 drive: DSB'-low;DSA-low: ' .
87
'.
88
90
I
92
.. ,93
94
95
96
97
98 -
99
100
DSA
OU,I
LA, .'
·In
[VDDj
V
CDS
.
In
.
RES!;T
In
SHB
In
S.HA", In
SREN
In
..
STNBY
Oul
,
#1 drive: DSB-Iow, DSA-high
#2 qrive: DSB-I)jgh,;
DS~>;IC\I'(
#3 drive: DSB-high, DSA-high
Determines logic of the drive sid_e.output
- .
.
. . WDT1, WE, HG, HL, MENO - MEN3, DSO -D53, STP, FR, LC, DR are active low wilh
a
high state 01
Il)js signal.
.
. , .
. .
. ' ..
'Single' +5\1 supply. AIIVbD lines are connected 10 +5\1 ..
Conlrol register DSs and
DsA
are selected as drive select Signal with a high slale ollhissignaL
lliiernal FDC block US1.and USOare selected as drive select signalwilh .. low slale 01 this Signal.
'Used
to
-indicate rate of shift for tli'e write.
Compensation circu,it" ,
'" _ 125ns when SHB is low andSHA low. '
250ns whenSHB is loiN arid SHA high.'
•. 3750s when SHB is high andSHA loW.
500ns when SHB is high and SHA hIgh.
One
halt
cif
the above
\ialu~s
is
used for the -standard 'floppy disk.
Used to set SHB and SHA valid. R;iite
01.
shift
becomes'b:for the write compensation circ;uit when the
signaL is at a hlghJevel.
. '.
.......
.
Indicates thallhe FDC is al standby.
. . : " ,
. ,
WDT1, WE, HG, HL, MENO - MEN3, DSO - DS:i, STP, FR, LC, DR are
activ~
low when in Ihe
standby mode.
.
WDT.
OUI'
FDD write data composed 01 clock bits and data' bits. .
ENID
Oul
Control regisler ENID .bil oulput.
C4.
.
_ Out
Conlrol registerC4. output.
. '.
.
.'
-5~-
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