Philips PCL304 - Main Board; Main Board Assembly

8
CIRCUIT
BOARD
ASSEMBLIES
(CBA)
8.1 Main Board
8.1.1.
Main
board
assembly
The
Main
Board
consists
of
the
following
systems:
CPU
(Central
Processing
Unit)
System Logic (HT-21)
ROM
(Read
only
Memory
)
BIOS
RAM
(Random
Access
Memory)
Real
Time
Clock
Generator
(DS-1287)
Keyboard
Controller
&
Encoder
(8042
&
80C51)
LCD/CRT
Controller
Interface
(CL-GD
610,
620)
Parallel
Port
&
Serial
Port
interface
(82C601)
Floppy
Disk
Interface
(8473)
The
80386SxX
is
used
for
the
system
CPU
(32
bit
micropro-
cessor)
and
the
CPU
clock
frequency
can
be
switched
for
low
speed
operation
from
the
standard
16
MHz
to
8
MHz.
The
ROM
BIOS
consists
of
one
128K
x
8
bit
EPROM
modu-
le.
The
standard
RAM
is
factory
installed
1
MB.
The
Liquid
Crystal
Display
(LCD)
controller
is
compatible
with
programs
that
use
the
IBM
Video
Graphics
Array.
The
floppy
disk
controller
provided
with
two
floppy
disk
dri-
ves
through
an
internal
FDD
interface
and
the
other
external
FDD
interface.
The
system
has
a
built-in
hard
disk
with
a
capacity
of
40
Me-
gabytes
(MB),
and
average
access
time
is
29ms.
8.1.2
Connector
pin
assignment
J1
25-Pin
Female
Connector
for
EXT.
FDD
[PinNo. |
an dea
Po
C3
nese
[s
[rp
|
ta,
ena
[6
|
-DoH
GND
7
=
_
—_
tht
CN2 96-Pin Connector for EXT. Bus
25
Pin No. Signa! Pin No. Signal
[4 ~—6[ Gupte. BALE
[2 | RESETDRV | 29. | :Sv
3. |45v | 30. =| oSc
| 4. | IRQS | 31. | GND
5s: [Nc | 32. ‘| lOcHCK
| 6. |: DRa2 | 33. | $7
| 7 |v | 34 ~‘| SD6
[8 |-ows | 35 |Sbs |
| 9. |[s5v | 36, _—s«|: Sw
[10 | Gnd | 37. _—i
sb2
[42 | -SMeMR | 39. =| Spi_— sd
3. |-low | 40. | SDo
4. |-lOR | 44. __| IOCHRDY
15. | -DACK3S | _——42._——s| AEN
|
46.
|
pros
|
43.__—'|
Satg9
[47. [| -Dacki | 4a._—sid|s S18
[1a |prar | 45 |SA7 |
[49 + +|-REF || S46. S| SAIS sd
| 20. | syscik | 47. __| SAIS
| at. | iRa7——id|S a. | SANA
| 22. ~[ Ross] S49. | SAB
23. | IRQs «| 50. ~— || SA12
24. | iRa4 | 51. | Satt
| as. | IRas.—i‘d|(C5. | SAMO
26. | -DACK2—|_—53._—«| Sag
[ a7. |to | 54 | Sae
| 55. | SA7_ «| —s76,__—*|- -DACK7
| 56. =| SAS | S77. |: DROZ
| sz. | sas | 78, -MASTER
[sa
[saa
|e.
-SBHE
| 59. | SA3 | 80. | ~LA23
[| 60. {saz | at. LA22
Tet. =| Sai | S| CLA
D~¢2. | sao. bao
| 63.__ | -MeMcsie | 84. LA19
[ 64. | -locsie | 85. CLANS
(ss. Tiroro | 2. LAI7
[
66.
|
iRai
—s«|_—87._—s|
-MEMR
[e67. [trai | sa.__—s| -MEMw
[Tse [ingis | 68. SD8
[69 [ima | 90. | Sd9
| 70. | -DAcKo | 91. | SDt0
a SDi1
| 72.~‘| -DACKs | _93._—sé{;:s S®2
[ 73. | pras | 94. | SD13
|
74.
|
packs
|
95.
|
§D15
75. | pros] 96. | S16
CS 55 819