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LC75886PWH-H

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P27P28-P30P31-P33P34-P36
LC75886PW
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16
Serial Data Output
1. When CL is stopped at the low level
2. When CL is stopped at the high level
CCB address ···· “43H”
KD1 to KD30 ··· Key data
SA ················ Sleep acknowledge data
Note: If a key data read operation is executed when DO is high (DO does not generate a key data read request output),
the read key data (KD1 to KD30) and sleep acknowledge data (SA) will be invalid.
Output Data
1. KD1 to KD30 … Key data
When a key matrix of up to 30 keys is formed from the KS1 to KS6 output pins and KI1 to KI5 input pins and one of
those keys is pressed, the key output data corresponding to that key will be set to 1. The table shows the relationship
between those pins and the key data bits.
KI1 KI2 KI3 KI4 KI5
KS1/S55 KD1 KD2 KD3 KD4 KD5
KS2/S56 KD6 KD7 KD8 KD9 KD10
KS3 KD11 KD12 KD13 KD14 KD15
KS4 KD16 KD17 KD18 KD19 KD20
KS5 KD21 KD22 KD23 KD24 KD25
KS6 KD26 KD27 KD28 KD29 KD30
When the KS1/S55 and KS2/S56 output pins are selected to be segment outputs by control data bits K0 and K1 and a
key matrix of up to 20 keys is formed using the KS3 to KS6 output pins and the KI1 to KI5 input pins, the KD1 to
KD10 key data bits will be set to 0.
2. SA … Sleep acknowledge data
This output data bit is set to the state when the key was pressed. Also, while DO will be low in this case, if serial
data is input and the mode is set (to normal or sleep mode) during this period, that mode will be set. SA will be 1 in
sleep mode and 0 in normal mode.
CE
A3 A2 A1 A0 B3 B2 B1 B0
KD2 KD1
X SA
KD30 KD29 KD28 KD27
0 1
DO
DI
CL
Output data
Note: B0 to B3, A0 to A3 … CCB address
X: don’t care
1 0 0 0 0 1
CE
A3 A2 A1 A0 B3 B2 B1 B0
KD2 KD1
X X
KD30 KD29 KD28
0 1
DO
DI
CL
Output data
Note: B0 to B3, A0 to A3 … CCB address
X:
n’t
r
1 0 0 0 0 1
KD3
SA
LC75886PW
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17
Sleep Mode Functions
Sleep mode is set up by setting S0 or S1 in the control data to 1. When sleep mode is set up, both the segment and
common outputs will go to the low level. In RC oscillator operating mode (OC=0), the oscillator on the OSC pin will
stop (although it will operate during key scan operations), and in exeternal clock operating mode (OC=1), acceptance of
the external clock signal on the OSC pin will stop (although the clock signal will be accepted during key scan
operations). Thus this mode reduces power consumption. However, the S1/P1 to S4/P4, P5/S57 output pins can be used
as general-purpose output ports under control of the P0 to P2, PC50 and PC51 bits in the control data even in sleep
mode (The P5/S57 output pin can not be used as clock output port). Sleep mode is cancelled by setting both S0 and S1
in control data to 0.
Key Scan Operation Functions
1. Key scan timing
The key scan period is 288T[s]. To reliably determine the on/off state of the keys, the LC75886PW scans the keys
twice and determines that a key has been pressed when the key data agrees. It outputs a key data read request (a low
level on DO) 615T[s] after starting a key scan. If the key data does not agree and a key was pressed at that point, it
scans the keys again. Thus the LC75886PW cannot detect a key press shorter than 615T[s].
Note: *3. These are set to the high or low level by the S0 and S1 bits in the control data.
Key scan output signals are not output from pins that are set to the low level.
Key on 576T[s]
*3
*3 *3
*3 *3
*3 *3
*3 *3
1 1
2 2
3 3
4 4
5 5
6 6
KS4
KS5
KS6
KS3
KS2
*3 KS1
T= =
1
f
OSC
1
f
CK
LC75886PW
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18
2. Normal mode, when key scan operations are enabled
(1) The KS1 to KS6 pins are set high. (See the description of the control data.)
(2) When a key is pressed, a key scan is started and the keys are scanned until all keys are released. Multiple key
presses are recognized by determining whether multiple key data bits are set.
(3) If a key is pressed for longer than 615T[s] (Where T=1/f
OSC
or T=1/f
CK
), the LC75886PW outputs a key data read
request (a low level on DO) to the controller. The controller acknowledges this request and reads the key data.
However, if CE is high during a serial data transfer, DO will be set high.
(4) After the controller reads the key data, the key data read request is cleared (DO is set high) and the LC75886PW
performs another key scan. Also note that DO, being an open-drain output, requires a pull-up resistor (between 1 and
10 k).
3. Sleep mode, when key scan operations are enabled
(1) The KS1 to KS6 pins are set to high or low level by the S0 and S1 bits in the control data.
(See the description of the control data.)
(2) If a key on one of the lines corresponding to a KS1 to KS6 pin which is set high is pressed, the oscillator on the OSC
pins starts in RC oscillator operating mode (the IC starts accepting the external clock signal in external clock
operating mode) and a key scan is performed. Keys are scanned until all keys are released.
Multiple key presses are recognized by determining whether multiple key data bits are set.
(3) If a key is pressed for longer than 615T[s] (Where T=1/f
OSC
or T=1/f
CK
), the LC75886PW outputs a key data read
request (a low level on DO) to the controller. The controller acknowledges this request and reads the key data.
However, if CE is high during a serial data transfer, DO will be set high.
(4) After the controller reads the key data, the key data read request is cleared (DO is set high) and the
LC75886PW performs another key scan. However, this does not clear sleep mode. Also note that DO, being an
open-drain output, requires a pull-up resistor (between 1 and 10 kΩ).
(5) Sleep mode key scan example
Example: S0=0, S1=1 (Sleep with only KS6 high)
Note: *4. These diodes are required to reliably recognize multiple key presses on the KS6 line when sleep mode state
with only KS6 high, as in the above example. That is, these diodes prevent incorrect operations due to sneak
currents in the KS6 key scan output signal when keys on the KS1 to KS5 lines are pressed at the same time.
Serial data transfer
Key data read request
Key data read
DO
DI
Key
address(43H)
CE
Key scan
Key input 2
Key input 1
615T[s] 615T[s]
(KSC=0)
615T[s]
Serial data transfer
(KSC=0)
Serial data transfer
(KSC=0)
Key
address(43H)
Key
address(43H)
Key data read request
Key data read Key data read
Key data read request
KI1
KI2
KI3
KI4
KI5
*4
“L” KS3
“H” KS6
“L” KS2
When any one of these keys is pressed, the
oscillator on the OSC pins starts in RC oscillator
operating mode (the IC starts accepting the external
clock signal in external clock operating mode) and a
key scan operation is performed
.
“L” KS1
“L” KS4
“L” KS5
T= =
1
f
OSC
1
f
CK
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P27P28-P30P31-P33P34-P36

LC75886PWH-H

Mfr. #:
Buy LC75886PWH-H
Manufacturer:
ON Semiconductor
Description:
LCD Drivers LCD DISPLAY DRIVER
Lifecycle:
New from this manufacturer.
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