
System Control Register A (Reg 3)
Reg: 3
Name: System Control Register A
Type: Write only.
BIT
LABEL
DESCRIPTION
@POR
0
SPIN_ENABLE
Enable spindle functions (1 = enabled; 0 = Disabled). Together
with VCM_ENABLE, determine the Normal, Idle or Sleep mode of
operation. See Mode Table for details.
0
1
VCM_ENABLE
Enable VCM functions (1 = enabled; 0 = Disabled). Together with
SPIN_ENABLE, determine the Normal, Idle or Sleep mode of
operation. See Mode Table for details.
0
2
SRESET
Reset spindle state machine (sequencer). 0=Reset. All spindle
and FLL registers are also reset. Also used to control the charge
pump (1 = off).
0
3
INCRE
A 0 to 1 transition of this bit increments the spindle state machine.
Normally used in SEARCH mode. Must be set to 1 in RUN Mode.
0
4
RUN_SRCH
1=Auto-increment enabled (RUN Mode)
0 = Auto-increment disabled (SEARCH MODE)
0
5
8_12P
Selects 8/12 pole motor: 1 = 8 pole, 0 = 12 pole
0
6
BIP_TRIP
Define Tristate, Bipolar, or Tripolar operation:
0
7
UNI_TRIP
See Spindle Drive Mode Table.
0
8
VCMRET
Activated VCM Retract: 1 = retract.
0
9
SPEED
Programs the Spindle Speed Control Method.
SPEED= 0: The L6260 operates open loop, with speed error
sensing performed externally and speed effort written into the
SPIN_DAC.
SPEED = 1: The speed is controlled internally through the built-in
control loop.
0
10
EL_MECH
Specifies electrical or mechanical cycle for the FLL control.
1 = Electrical, 0 = Mechanical
0
11
TEST_COUNT_RESET
Writing a 0 resets the test sequence. Must be set to 1 to allow
ATEST and DTEST functions.
0
MODE OF OPERATION (REGISTER 3 BITS 0 AND 1)
SPIN_ENABLE
VCM_ENABLE
MODE
DESCRIPTION
(0) DISABLED
SLEEP
MINIMUM POWER DISSIPATION.
(0) DISABLED
(1) ENABLED
NOT NORMAL
VCM IS FORCED TO A PARK CONDITION
(1) ENABLED
(0) DISABLED
IDLE
VCM DISABLED FOR REDUCED DISSIPATION
(1) ENABLED
NORMAL
NORMAL MODE OF OPERATION
SPINDLE DRIVE MODE (REGISTER 3 BITS 6 AND 7)
BIP_TRIP
UNI_TRIP
SPINDLE DRIVE MODE
0
TRISTATE
0
1
NOT DEFINED
1
0
BIPOLAR
1
TRIPOLAR
L6260
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