UPD16432B NEC, UPD16432B Datasheet - Page 10

• Manufacturer Part Number: UPD16432B
• Description: 1/8/ 1/15 DUTY LCD CONTROLLER/DRIVER
• Manufacturer: NEC

KEY REQUEST (KEY REQ)
LED OUTPUT LATCH CONFIGURATION
10
In key scan operation
In standby mode or when SEG
& COM
When key scanning is stopped
A key request is output as shown below according to the state.
Note KEY REQ does not become low until the key data is all “0”.
The low-order 4 bits of the LED output latch are enabled, and the high-order 4 bits disabled, as shown below.
Latch data is as follows:
MSB
n
are fixed at V
(It is not synchronized with the key data reads.)
State
1: On
0: Off
LC5
b3
n
b2
High level is output while any key
data is “1”.
High level is output in case of key
input only.
Fixed at low level
b1
LSB
b0
Note
KEY REQ
LED
LED
LED
LED
Note
: Don’t Care
1
2
3
4
During key scan : ON
During display
Always ON
Always OFF
Key Scan Internal Pull-Up Resistor
: OFF
PD16432B