hd66717 Renesas Electronics Corporation., hd66717 Datasheet - Page 76

• Manufacturer Part Number: hd66717
• Description: Low-power Dot-matrix Liquid Crystal Display Controller/driver -
• Manufacturer: Renesas Electronics Corporation.

HD66717
Standby Mode
Setting the standby mode bit (STB) to 1 puts the HD66717 in standby mode, where the device stops
completely, halting all internal operations including the R-C oscillator, thus further reducing current
consumption compared to that in sleep mode. Specifically, character and segment displays, which are
controlled by the multiplexing drive method, are completely halted. Here, all the SEG (SEG1 to SEG60)
and COM (COM4 to COM34) pins output the V
in standby mode, the LCD drive power supply can be turned off.
Annunciators can be displayed simply by supplying an approximately 40-Hz alternating signal for the
LCD drive signals to the EXM pin externally. If annunciator display is unnecessary during standby mode,
the EXM pin must be fixed to the V
During standby mode, no instructions can be accepted other than those for annunciator display and the
start-oscillator instruction. To cancel standby mode, issue the start-oscillator instruction to stabilize R-C
oscillation before setting the STB bit to 0.
Figure 45 shows the procedure for setting and cancelling standby mode.
528
Standby mode (only annunciator display is available)
Supply an external alternating signal to the EXM pin
Figure 45 Procedure for Setting and Cancelling Standby Mode
Turn on the LCD drive power supply: AMP = 1
Turn off the LCD power supply: AMP = 0
Issue the start-oscillator instruction
Cancel standby mode: STB = 0
Set standby mode: STB = 1
Wait at least 10 ms
CC
or GND level and the annunciator display-on bit (DA) set to 0.
CC
level, resulting in no display. If the AMP bit is set to 0
Only for annunciator display;
set the DA bit to 0 when
annunciator display is not necessary.