PD17012_15 Datasheet, PDF (238/320 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCONTROLLERS WITH DIGITAL TUNING SYSTEM HARDWARE

µPD17012, 17P012
20.4.3 Configuration and function of LCD mode select register
The LCD mode select register turns on/off all the LCD display dots, and specifies output of the key source
signal.
The configuration and function of this register are illustrated below.
Name
LCD mode select
register
Flag symbol Address
b3 b2 b1 b0
0KLP
10H
SCY
EDA
NES
NE
L
Read/
write
R/W
Selects LCD segment output pin and general-purpose output port
0 Pins LCD0/KS0/PYA0 to LCD15/KS15/PYA15 used as LCD segment
1 Pins LCD0/KS0/PYA0 to LCD15/KS15/PYA15 used as general-purpose output port
Turns on/off all LCD display
0
Display off (all segment and common output pins output low level)
1
Display on
Selects output of key source signal
0
Key source off
1
Key source on
Fixed to 0
Power-on
Clock stop
CE
0000
0000
Retained
20.4.4 Output waveforms of segment and key source signals
Figures 20-5 and 20-6 show the output waveforms of the key source and segment signals.
As shown in figures, the key source and segment signals are output by means of time-division multiplexing.
The key source signal is output for 220 µs at intervals of 4 ms.
To put it in another way, a pin corresponding to a bit of the key source data register that is set to 1 outputs
a high level for 220 µs every 4 ms, and a pin corresponding to a bit of the key source data register that is reset
to 0 outputs a low level for 220 µs every 4 ms.
When output of the key source signal is selected (KSEN flag = 1), pins that do not output key source signals
(LCD19/P2H0 to LCD16/P2E0) output the waveform shown in Figure 20-6. However, a waveform of 0 is output
as the key source data.
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Data Sheet U10101EJ4V0DS