(2) The HD61202 LCD driver is for the 6800 series; the
timing clock E required for this interface is sent from
the SC7852.
The clock E goes high when the Z-80 accesses 40H-
5FH of
1/0,
(lt has a half clock delay against
10RQ
and its pulse width is 540 nanoseconds.)
But, the HD61102 will not be selected unless all three
chip select lines (CS1, CS2, CS3) are enabled. Two
HD61102s have the following address inputs as shown
in the next table.
-----
HD61102 (lC2)
HD61102 (IC3)
CS1 A2
A3
CS2
A5
A5
CS3 A4
A4
Selected
1/0
space
50H - 53H
50H - 53H
58H - 5BH 54H - 57H
(3) For the LCD drive voltage, VCC-VEE are divided by
a resistor to obtain the LCD drive voltages, Vl-V6
and VEE.
VEE is derived from the power supply hybrid IC
50347C.
Vcc
(4~4. 7V) R 1
VI
(HD61203(S), HD61102)
V6
(HD61203 )
V3
(HD61l02 )
V5
(HD61203 )
V4
(HD61102 )
V2
(HD61203(S), HD61102)
R2
R3
R4
R5
VR
VEE VEE (HD61203(S),HD61102'
( =
-8.5V)
7-5. Keyboard block
7-5-1. Key scan timings
Keyboard key scan is done by a Z-80 interrupt with a 1/64
second timer interrupt (subcontroller output INT4).
7-5-2. Method of scanning
Nine key
strebe
signals are obtarneo through
PA7-PAO
anu
PB6 of the SC7852
1/0
port.
Key scan is done in the following ways:
CD
Only the strobe signal of the Y row to be scanned is set
low with other strobe signals set for the input mode.
®
To scan another strobe row after the current strobing
row, a high signal is issued to that strobing row first,
-13-
-
PC-l600
then set in the input mode. So, a low signal is issued to
PA7 - PAO and PB6 at every 1/64 second to discri-
minate a key depression. In this instance, a low signal
is sent to all strobe lines to sense a key depression.
When a key depression is sensed, that particular key is
distinguished after sending astrobe to each line.
As the key input appears on KIN7-KINO of the
SC7852, a row of the keys in a low state is judged to be
the row at which the key entry occurred. Since input
not having a key entry is internally pulled up in the
LSI, it is in a high level.
7-6. Buzzer block
7-6-1. General
These two lines activate the buzzer.
• PC6 output of the SC7852
• Subcontroller F output
7-6-2. Description
As the buzzer is sandwiched between two lines, oscillation
from either line causes the buzzer to activate. Consumption
current is 3 mA, maximum.
(Conditions: Input voltage
=
4.5Vp-p square wave, input
frequency
=
4.1 KHz)
PC6-@-F
(1) PC6
The following three signal sources are connected to this
line.
CD
PB2 Cassette playback signal
® PC7 Cassette recording signal and beep by a
BEEP statement
® SDO ..... Recording signal by the CE-150 or CE-
162E
But, when the beep is turned off, sound is not
generated no matter what the above signals may be.
The above three signallines are normally high.
(2) F
The following three signal sources are connected to this
line.
Ci)
Click .... In the dick mode, a dick is generated
each time a key is pushed.
® Sound generated upon wake-up,
®
Sound generated before issuing an alarm message.
Norrnallv , these three lines are low.
7-7. RS-232C interface and SIO interface
The following serial interfaces are provided for the PC-
1600.
(1) RS-232C
Interface
(COM 1 :)
(2) SIO interface (COM2:)
It incorporates the UART TC8576T as the hardware.
While the PC·1600 has two interfaces with single supported
channel, only one interface can be active at one time. The
OPEN or SETDEV statement is used to selectively activate
the channel and the PR IME signal is used to activate the
hardware.
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