Clock - Sharp PC-1600 Service Manual

Pin
Symbol
No.
24 CKOS
VCC
25
GNO
26
BRQ
27
28-30 00-02
31-35 03-07
c/5
36
37 10RP
38 CL
39 A13
A14
40
41 OSR
42 CLKl
43 KH
44 A13A
45-47 A14A-A16A
48-50 LHS1-LHS3
51-53 KAO-K2
54-56 Sl-S3
59-61 KO-K2
62 ME1
63 MEO
00
64
Active
ln/Out
level
The 00 signal indicates that the CPU (LH5803)
In
writing, So, it may possibly be at a low level when not reading, and it also may not
match the Z-80's timing during data input/output
To prevent these problerns,
memory or 1/0 is created with five signal (MEO, ME1, 00,
-
Power supply (Input of VGG of the system),
-
Power supply.
In See Pin No. 24.
Z-80 data bus.
ln/Out
Out When the sub CPU outpur
a high level, 02-
system-off
c(B
In High The line 01 the SC7852 goes high when the Z-80 wirites 30H of the 1/0.
In Low The signal used to send R33-
It goes low when the Z-80 reads 33H 01 the 1/0.
In Low System reset input. When this signal is at a low level, it forces A 16A to high, A 15A
to low, and A14A to high.
In CPU address A 13.
Input of the CPU address A14 (insigni1icant).
In
Out
Not used.
Out When the system is on, CL2 is issued on this line and becomes the basic clock for the
UART. A low is on this line when the system is off.
Out High Opposite polaritv
Out Opposite polarity
Out C/O latched
Also, A 16A is used for separating
7FFFH (bank 3) into two banks.
In Low Memory select and 1/0 select signals from the SC7852 are sent to slots of S1: and
In Low S2: via the gate arrav. The reason why is that it has to be set at a high level at
system-off
(1 )
When the system is on but not in a weak battery
signal appears on S1, S2, S3, KO, K1, and K2.
(2)
All are high when the system is off or a weak battery
Out Low LHS1-KA2
Out Low All are high outputs
In
In See pin NO.24.
In
-!-\1-
Function
the signal goes low only when the LH;5803
P1 (SLCB), wh ich is sent out when the system is off, is at
00 become low, thus fixing the level of the .input sinal during
as 02 - 00 are inputs also.
R20 on the Z-80 data bus.
of the BREAK/ON key Input is sent to the sub CPU.
of the A 13 input is sent.
02-00 outpur.
CS24
the
as the SC7852 power supply is shut off when the system is off.
outputs,
when the system is off.
------- --------
-
P C-l600
read timing is at a low level when not
of the SC7852 internal data.
is reading the
CKOS, and BR05).
selected 16KB memory space 4000H-
condition the status of each
is detected.
I
!
!