SM565 View Datasheet(PDF) - Sharp Electronics
Part Name
Description
Manufacturer
SM565 Datasheet PDF : 20 Pages
| |||
4-Bit Single-Chip Microcomputer
LCD Driving Signal Waveform
Figure 16 shows the LCD signal driving waveforms
required to display the number ‘5’ on the 7-segment
display shown in Figure 14 (segment outputs S0 and S1
are used). A voltage of 3 V is applied to pin VDSP in Fig-
ure 16. The frame frequency (I/T) can be selected from
64 Hz or 128 Hz by mask options.
VOA and VOB
The device contains bleeder resistors to allow 1/3
bias driving. When VDSP is 3 V, voltages of 2 V and 1 V
are output from pins VOA and VOB respectively. Nor-
mally pins VOA and VOB are left open. When a LCD with
a large display area is driven, connect capacitors across
pins VOA and VDSP, and across VOB and VDSP to
improve the rise time of the LCD driving signal.
Remote Control Carrier Output Function
SM565 has a carrier output function for remote con-
trol output. A carrier is output from ΦOUT, and con-
trolled using the register R73. Setting ‘0’ in the bit of
R73 causes the output from ΦOUT to be set constant
HIGH output. If ‘1’ is set, a carrier, which is a remote
control signal, is output. If ‘0’ is set in the bit of R73, the
output level is set constant HIGH as stated above.
However, it can be set to constant LOW level using the
mask option.
Either 1/2 or 1/3 can be selected as the duty of the
carrier. (See Table 2 and Figure 17.)
The frequency of the carrier is approximately
37.9 kHz (1/2 duty or 1/3 duty) when the basic oscilla-
tion frequency (main clock) is 455 kHz.
Figure 18 shows an example of a circuit that con-
verts remote control carrier signal from the ΦOUT pin
into infrared signal.
Table 2. Mask Option for ΦOUT Pin Output
Selection of PLA
PLA1 PLA2
ΦOUT OUTPUT
Output When Remote Control
Waveform Signal is Not Output
1
1
A
Constant LOW output
2
1
B
Constant LOW output
1
2
A
Constant HIGH output
2
2
B
Constant HIGH output
T
H1
H2
H3
H4
S0
S1
SM565
VDSP (3 V)
VOA (2 V)
VOB (1 V)
GND (0 V)
VDSP
VOA
VOB
GND
VDSP
VOA
VOB
GND
VDSP
VOA
VOB
GND
VDSP
VOA
VOB
GND
VDSP
VOA
VOB
GND
H1
H2
H3
H4
S0
S1
565-18
Figure 16. LCD Driving Signal Waveform
(Required to Display the Number 5)
Microcomputer Data Sheet
15
Share Link: 