Sharp PC-1600, Service Manual

Page: 32 / 118

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PC-1600
Pin
Symbol
ln/Out
Active State
Function
No. level
at ACL
38 KC3 In Not used.
39 KC2
In Used for checking the CE-1600P power supply level. VPP supplied from
the CE·1600P via the system bus is A/O converted. If it is below the given
level, the peripheral is assumed to have a weak battery condition.
40 KCl In Used for checking the PC·1600 main power supply level. The level of the
main power supply is A/O converted and checked. If it is below the given
level, a weak battery condition is assumed.
41 KCO In Receives the signal input from the analog input connector.
(1)
For the analog input, A/O conversion is done.
(2)
For the external keyboard input, its logic level is interrogated.
42
R33
Out
In MSB
43 R32 Out In
44 R31 Out In
45 R30 Out In
Return data to the Z-80.
46 R23 Out
In
47 R22 Out In
48
R21 Out In
49 R20 Out In LSB
50
VRL NC
51 SIN In NC
52 VOO High power supply voltage level (VGG).
53 R13 In In MSB
54 R12 In In
55 Rll In In
56 Rl0 In
In
Command from the Z-80.
57
R03 In In
58
R02 In In
59 ROl In In
60 ROO In In LSB
61
Q3 In Low In Hardware sensed weak battery detection signal.
A high on this line causesthe CPU to force the system to go down. The only
means to turn the svstern on after recovery of power supply is the depression
of the BREAK/ON key or ALL RESET switch. The time in the real-time
timer would not be revised.
62 Q2
In In Not used. Pulled down.
63
Ql In Low In Opposite polarity as CI of the R5-232C interface. It is possible with CI to
turn on the system when the system is off (when this line is at a low level).
64 QO In Low In 1fthis signal is at a low level when the system-off command is received from
the Z-80, the system is turned off.
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