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A13
Al4
28
48
[A19
29
15
_|-WE/-PGM |Write enable
30
49
_|A20
31
16
|+RDY/-BSY |Ready/busy
(AREQ interruption request)
32
50
|A2t
5V
5V
35
18
|VPPt
Program power
(Power for peripheral devices)
36
52
|vPP2
Program power
(Power for peripheral devices)
37
19
|At6
38
53
[azz
39
20
|A15
[40
54
[A23
41
21
Al2
L 42
55
A24
43
22
[AZ
44
56
_[AQ5
45
23_|A6
46
$7
_|RFU
Reserved
47
24
48
58
49
25
50
59
PCMCIA function. () shows
PCMCIA function. () shows
the function when the I/O card.
arrange- | PinNo. | PCMCIA | the function
when the I/O card
is operating.
ment
_|__isoperating.
51
26
[a3
52
60
_|(4NPACK)
[Reserved (input response)
53
27
[a2
54
61
-REG
Attribute memory space select
55
28
fat
56
62
|Bvo2
Battery voltage detection
(-SPKR digital sound signal)
57
29
[Ao
58
63
|Bvo1
Battery voltage detection
(-STSCHG card state change)
59
30
[D0
60
64
[08
61
31
[01
62
| 65
[o9
Ce
64
66
|D10
arena
65
33
|+wP
Weite protect (16 bit VO port)
Raven
66
67
_|-co2
Card detection
67
34
[GND
Reservation (I/O READ)
ke
J
21
11
[a9
IC card connector
22
45
|(-4/OWR) __ | Reservation (/O WRITE)
Pin No.
23
12
[as
24
46
[A17
IC card connector
* Be careful that the pin arrangement of the IC card connector is
irregular as shown above.
11. Sound control
JUNIOR-1 sound output system is of 8 bit PWM using 10MHz as the
basic clock. Sound PWM
signal is generated inside the ASIC and
outputted to IC4.
One of two operation amplifiers of IC4 is used as the low pass filter,
and the other is used as the amplifier. The low pass filter charac-
teristics are determined by R6, R7, R8, CS, C6, and C7.
The PWM output from the ASIC is passed through the low pas filter
and decoded. The decoded output is amplified by the amplifier and
passed through jC1 to operate the speaker. The amplification ratio
from the ASIC to the speaker is determined by the resistance ratio of
R78 and R79, and the resistance ratio of R1, R2, R3, and R4. Con-
nection of R1 and R2 to the circuit is controlled by two analog
'switches (IC38 and IC40), supplying four levels of amplification ratio.
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