Sharp R-4A52 Service Manual page 19

R -4A52
R-4E52
DESCRIPTION OF LSI
LSI( IZA312DR)
The I/O signals of the LSI(IZA312DR) are detailed in the following table,
PIN NO. / 1
__ ---- __-.--
1 SIGNAL 1 T
I
l/O
j OUT '
Signal to sound buzzer.
A: Key touch sound (0.12 sec.).
6: Completion sound (2.4 sec.).
PIN NO. j 2
1 SIGNAL / VDD
------ - _____
Power source voitaqe: -12V
VDD voltage of power source circuit input.
I
l/O
/ IN
PIN NO. i 3 I.-SIGNAL / VREF
I
l/O
IN
A-_-
Reference voltace input terminal.
'A reference voltage applied to the A/D converter in the LSI. The reference voltage is generally maintained at -6.15V
PIN NO.
i 4
~~-.-.-.-_I_
1 SIGNAL j VP
I
I/O
/ IN
I
Anode (segment) of Fluorescent Displav illumination voltaqe: -27V
Vp voltage of power source circuit input.
PIN NO. 1 5
1 SIGNAL / INT
I
I/O
IN
Signal svnchronized with commercial source frequency(50Hz).
This is the basic timing for time processing of LSI.
PIN NO. / 6
1
SIGNAL 1 CNVSS
I I/O
1 IN
_-- _______- -
Power source voltage input terminal.
Connected to GND.
PIN NO. / 7-10 1 SIGNAL / FO-F3
I I/O
1 OUT
Segment data signals.
Refer to the touch control panel circuit for the relationship between signals and indicators.
Normally, one pulse is output in every synchronized signal period, and input to the anode of the fluorescent display.
PIN NO. 1 11
1 SIGNAL / SO
I I/O
1 OUT
Segment data signal.
Signal similar to FO.
Key strobe signal.
Signal applied to touch-key section.
A pulse signal is input to K4-K7 terminal while one of D-8 line keys on key matrix is touched.
Terminal not used.
PIN NO. 12
Segment data signal.
Signal similar to FO.
Key strobe signal.
1 SIGNAL j Sl
I I/O
/ OUT
Signal applied to touch-key section.
A pulse signal is input to K4-K7 terminal while one of D-7 line keys on key matrix is touched.
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