UPD16434 NEC, UPD16434 Datasheet - Page 35

• Manufacturer Part Number: UPD16434
• Description: 1/8/ 1/16 DUTY LCD CONTROLLER/DRIVER
• Manufacturer: NEC

7. STANDBY MODE
not necessary.
signal is set to high after the STOP command is executed. In the standby mode, the
CLOCK signal to the LCD timing control circuit and the clock control circuit by internally masking the CLOCK signal. In
addition, the
other modes are affected by RESET operation, so that the interface mode and the display mode will be retained. The
standby mode is cleared when a byte of data (command or data) is input, or when the RESET signal falls. However, the
processing necessary during the standby mode and operation after clearing the standby mode differ, depending on which
method is used.
consumption can be further reduced, compared to when the CLOCK is only internally masked.
7.1 Clearing Standby Mode
(1) Clearing standby mode by writing a byte of data
The
The standby mode is set, by executing the STOP command. The standby mode is actually set, when the /BUSY
In addition, the CLOCK signal to the
needs to be maintained, the standby mode can be cleared by writing a byte of data (command or data).
rising edge of the 8th /SCK). In the parallel interface, the standby mode is cleared, when writing the second 4-bit
data is completed (at the rising edge of the 2nd /STB).
mode, the first 8-bit data, after /CS is set to low, is used as the chip address information, when the standby mode
is cleared. Therefore, the standby mode is cleared, when writing the next 8-bit data is completed.
Remark During the standby mode, the clock necessary for driving the LCD by alternating current is stopped.
In the serial interface mode, the standby mode is cleared, when writing 8 bits of serial data is completed (at the
When the chip address selection function is used in the serial interface mode, if /CS is set to high in the standby
If the previous operation modes (except the data processing mode), used before entering the standby mode,
PD16434 offers the standby mode in order to reduce the power consumption, when displaying operation is
Therefore, the LCD drive signal level, before entering the standby mode, is maintained in the standby
mode. This means that a DC voltage remains applied to the LCD in the standby mode. To avoid this,
control the V
level from the output port, before executing the STOP command, to eliminate voltage differential
between the V
PD16434 initializes the data processing mode to the auto-increment (I
LC5
DD
pin voltage using the CPU output port, as shown in Figure7–1, and output a high
and V
LC5
.
PD16434 can be stopped during the standby mode. In this case, the power
Data Sheet S10299EJ4V0DS00
1
I
0
= 00) write mode. However, no
PD16434 stops supplying the
PD16434
35