PD17012_15 Datasheet, PDF (233/320 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCONTROLLERS WITH DIGITAL TUNING SYSTEM HARDWARE

µPD17012, 17P012
20. KEY SOURCE CONTROLLER/DECODER
The key source controller/decoder can configure a key matrix of up to 64 keys by outputting key source signals
by means of the LCD segment signal output and time division.
20.1 Configuration of Key Source Controller/Decoder
Figure 20-1 shows the configuration of the key source controller/decoder.
As shown in the figure, the key source controller/decoder consists of a segment signal/general-purpose
output port select block, segment signal/key source signal timing control block, key source data register, key
input control block, and P0D port register.
The following section 20.2 outlines the function of each block.
Figure 20-1. Outline of Key Source Controller/Decoder
PYASEL flag
LCDEN flag
KSEN flag
LCD15/KS15/PYA15
LCD14/KS14/PYA14
.....
LCD2/KS2/PYA2
LCD1/KS1/PYA1
LCD0/KS0/PYA0
.........
P0D3/K3
Key matrix
P0D2/K2
P0D1/K1
P0D0/K0
Segment signal/
general-purpose
output port
select block
Segment
signal/key
source signal
output timing
control block
From LCD
segment register
Key source
data register
(KSR)
DBF
Key input
control block
KEYJ flag
P0D port register
(data memory)
Remarks 1. PYASEL (bit 0 of the LCD mode select register; refer to 20.4.3 Configuration and function of
LCD mode select register) sets the LCD15/KS15/PYA15 to LCD0/KS0/PYA0 pins in the LCD segment
signal output or general-purpose output port mode.
2. LCDEN (bit 1 of the LCD mode select register; refer to 20.4.3 Configuration and function of LCD
mode select register) turns ON/OFF all LCD displays.
3. KSEN (bit 1 of the LCD mode select register; refer to 20.4.3 Configuration and function of LCD
mode select register) sets output of the key source signal.
4. KEYJ (bit 0 of the key input judge register; refer to 20.5.3 Configuration and function of key input
judge register) detects whether the latch contents of the key input pin are valid.
Data Sheet U10101EJ4V0DS
231