Focus Drive; Focus Search Communications - Sony DVP S530D Training Manual

Focus Drive

Servo IC701 outputs two square waves from pins 80 and 85 as long as
the set is powered. The reference square wave comes from pin 80 and is
fixed at 50% duty cycle. When the duty cycle of pin 85's waveform changes,
the focus coil receives current.
The following waveforms were taken during focus search. Note that the
falling edge of the reference waveform (ch 2) is always in line with the
drive signal (ch 3) from pin 85.
P M 3 3 9 4 , F L U K E & P H I L I P S
c h 2 : f r e q = 7 9 . 4 k H z
c h 2
c h 3
2
T
3
C H 2 ! 2 . 0 0 V =
C H 3 ! 2 . 0 0 V = A L T M T B 2 . 0 0 u s - 1 . 1 6 d v c h 3 -
Focus Search Waveforms
Name
Channel 2 FCD -
Channel 3 FCD +
Time base
This second group of waveforms compares the input and output of the
driver IC801 during playback. When there is a change to the duty cycle of
pin 9's waveform, there is a differential voltage applied to the focus coil.
P M 3 3 9 4 , F L U K E & P H I L I P S
c h 1 : p k p k = 3 . 8 0 V
c h 1
c h 1 : f r e q = 7 9 . 4 k H z
c h 2
1
c h 3
c h 4 T
2
3
C H 1 ! 2 . 0 0 V =
C H 2 ! 2 . 0 0 V =
4
C H 3 ! 1 . 0 0 V ~
C H 4 ! 1 . 0 0 V ~ A L T M T B 5 . 0 0 u s - 0 . 9 4 d v c h 2 +
Location Voltage/div
IC701/pin 80 2Vp-p
IC701/pin 85 2Vp-p
2usec/div.
57
Focus Driver IC801 Input/Output
Name
Channel 1 FCD -
Channel 2 FCD +
Channel 3 + DO 1
Channel 4 - DO 1
Time base
Driver IC801 supplies the current to the focus coil within the optical base
assembly. The spring suspended focus coil is attached to the lens posi-
tioned next to a stationary magnet. The lens is moved when current is
applied to the coil. Lens movement changes the laser's focal point.

Focus Search Communications

System Control IC202 to Servo IC701
During focus search, bi-directional communications take place between
IC202 and IC701. Since the number of output ports IC202 has is limited,
HGA IC601 is used as an expansion port to control the flow of bi-direc-
tional information to and from destination ICs such as IC701. All three
ICs share a common address and data bus. The information placed on
the bus is time-shared by each IC. The time is controlled by System
Control IC202.
System Control IC202 to HGA IC701
IC202 cannot communicate with IC701 directly to control servo opera-
tions. It must use a middleman - IC601. IC601 handles so many opera-
tions it is electronically divided, having two chip select inputs.
When IC202 wants to send data to IC601, IC202 must also send chip
select, clock, write pulses and address information to support the data.
Location Voltage/div
IC701/pin 80 2Vp-p
IC701/pin 85 2Vp-p
CN003/pin 12 1Vp-p AC coupled
CN003/pin 13 1Vp-p AC coupled
5usec/div.