Philips DVDR9000H/75 Service Manual page 197

9.5.5. Power Supply
The Digital board is not powered in standby mode. The
control signal STBY on the analog board will enable the PSU
and power the digital board.
•
STBY = High : the digital board is in powered down
standby mode
•
STBY = Low : the power supply to the digital board
is enabled. The 3V3, -5V, +5V and
+12V come from the PSU, while the
following voltages are generated in the
digital board:
•
1.8V core voltage generated by a NCP1571D [7501] .
It provides a DC-DC power solution producing a 1.8V
output voltage over a wide current range
9.5.7. Reset
3V3
7106
NCP303
Reset concept Digital board
The voltage detector NCP303LSN29 [7106] provides the
reset signal PNX7100_RESETn with the correct timing
behavior. This circuitry functions as a Power-on reset module
which detects the minimum functional voltage that is needed
by the device. It also detects any voltage drop. When the
power voltage is outside the nominal range, a reset signal is
generated and fed to the Chrysalis chip to reset the different
peripherals and processing units.
•
PNX7100_RESETn = High {the Digital board is up and
running}
•
PNX7100_RESETn = Low {the Digital board will reset}
There are two control lines which can overrule this reset
signal:
•
IRESET_DIG (controlled by the microprocessor on the
Analog Board)
•
EJTAG_RESETn (only for production)
The PNX7100_SYS_RESETn is a general enabling signal
for the different reset lines. All other reset lines are directly
driven from the Chrysalis port pins. All reset lines are logically
connected via 74LVC08AD [7104 and 7107] AND-gates. If both
reset signals are low, all other external devices are initialized.
Circuit- and IC description
7400
>1
PNX7100_RESETn
CHRYSALIS
PNX7100EH
Figure 9-6 Reset concept
3139 785 31681
•
1.8V_VIP generated by LD1117D18 [7008] for the VIP
•
3.3V_VIP generated by LD1117D33 [7006] for the VIP
•
2.5V generated by a LF25CDT [7600] for Pro-scan Video
Encoder
9.5.6. Memory
Several memories are used on the Digital Board:
•
Eeprom IC [7809] : this memory contains all the
parameters for the application
•
Eeprom IC [7810] : this memory contains the boot
parameters of the board
•
Flash IC [7807] : this memory contains the application
and Service diagnostic fi rmware
3V3_RES
GPIO
PNX7100_SYS_RESETn
9.5.8. In/Out Connector
Audio In/Out Connector [1900]
The Audio In / Out (AIO) connector is used to interchange
digital audio signals between the Analog and Digital board.
Video In/Out Connector [1904]
The Video In / Out (VIO) Connector is used to interchange
analogue video signals between the Analog and Digital board.
Video Out Connector [1002]
The Video Out Connector is used for Progressive Scan video
signals to the Analog board
9.5.9. Service UART Interface
Hex Inverting Schmitt trigger 74HCT14D [7111] are used to
make a level conversion between LVTTL and 5V (compatible
with most RS232 interfaces) and vice versa. The control
line MPIO19_EEPROM_En is used to activate service and
diagnostic SW at start-up. The connectivity is provided via an
external service tool.
9. EN 197
RESET_IDE1n
7104-3
&
RESET_1394n
7104-4
&
RESET_DTTMn
7107-1
&
RESET_PROGSCANn
7107-2
&
ANALOG_RESETn
7107-3
&
VIP_RESETn
7104-1
&
RESET_IDE2n
7104-2
&