PD17012_15 Datasheet, PDF (259/320 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCONTROLLERS WITH DIGITAL TUNING SYSTEM HARDWARE

µPD17012, 17P012
(2) Notes on multiplexing LCD segment signal and key source signal outputs
P0D3/K3
P0D2/K2
P0D1/K1
P0D0/K0
LCD15/KS15/PYA15
Latch
H
LCD segment
signal output _L
waveform
LCD segment signal
220 µ s
Key source signal
Execute the HALT 0001B instruction after setting key source signal output data.
At this time, the halt status is not released even if a high level of the LCD segment signal is input to the
pin whose key source signal output data is “0”.
To multiplex an LCD segment signal output with a key source signal output, set the KSEN flag of the LCD
mode select register to 1.
The key source signal data (setting the pin that outputs a key source) is set by the key source data register
(KSR: peripheral address 42H) via the data buffer.
The internal key latch circuit when an LCD segment signal output is multiplexed with a key source signal
output latches data only while the key source signal is output, and is disconnected from the external
source while the LCD segment signal is output.
The internal pull-down resistor is on only when the key source signal is output.
(3) When releasing from halt status using other microcontrollers
Output port
Microcontroller, etc.
P0D3/K3
Latch
P0D2/K2
P0D1/K1
P0D0/K0
General-purpose output port or LCD segment signal output
The P0D0/K0 to P0D3/K3 pins can also be used as general-purpose input port pins with pull-down
resistors.
Therefore, the halt status can also be released by using other microcontrollers as shown above.
Data Sheet U10101EJ4V0DS
257