PCC D3400 - Page 102

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I
I
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I DEMAND
I ADDRESS
I (ICDnR)
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DEMAND
ADDRESS
REGISTER
PORTION •
DEMAND
ADDRESS
MOST SIGNIFICANT
(LDAMGI
OF
r-~SP~R~C~G-~~
SERVO
r-
•
-.
PORTION
OF
READIWRITE
•
PCBA
-;]..,
L _______ T
COUNT
PCBA
SPQCG
CONTROL
"1:' _____ _
1
LOAD OR PURGE NOT NLLPNGI-------~
r--------,
I PORTION OF J,.
~ TEMPERATURE
. - I COMPENSATION
I PCBA .,
L _________ J
SUBTRACTOR
AND
COMPLEMENTOR
CURRENT
ADDRESS
CARRY
CONTROL
COUNTER
I-----_~SEEK TIME ERROR (NLSTEGI
ERROR
CHECK LOGIC
I-----_~POSITION LIMIT ERROR (NLPLEGI
ADDRESS DIFFERENCE (NLADnGI
FORWARD DIRECTION (LFDXI)
r - ------
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I
I
,
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I
I
I
I
I
PORTION
OF
SERVO
PCBA
VALID
I
,
•
1 fr-----------------------------~-----------I-----
POR,. TlON L...;S~PT:!.I~G:....., ... ..a-~-.L-...I~L---'--"'"II
VELOCITY REFERENCE ENABLE (NLVREGI
OF
I -- r-.....;..~~;;..:;.;.:.:;.:.::::..::.:.:.:::.::.::~:..:.:.:.~-------I~
I SHRXG POSITION MODE (LPMXGI
LOAD
ADDRESS
AND
ILLEGAL ADDRESS
CONTROL
ADDRESS
--
t----~ILLEGAL ADDRESS (NLIAXGI
DECODERS
__ i~_C_Y_L_IN_D_E_R_A_D~D_R~E~SS~ST~RO~B~E~(~IC~AS~RI~ ___ ~~ ________ t-------------------.
I --
I
BUSY LOGIC
I
I RESTORE INITIAL CYLINDER (IRICRI
I----_~BUSY SIGNAL (NLBSXGI
SERVOPCBA
LOAD
,HEADS (LLHFFI----I~
I
LOAD HEADS (NLLHFFI---,,001
MODE CONTROL
I ----------
OPERATION CONTROL
--
~~------------------~
FORWARD SLOW MODE (NLFSMI)
REVERSE SLOW MODE (NLRSMI)
I
~
I
L _____ _
Figure 4-11. Position Control Logic,
Functional Block Diagram
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