HD66750 Datasheet, PDF (81/96 Pages) Hitachi Semiconductor – 128 x 128-dot Graphics LCD Controller/Driver with Four-grayscale Functions

HD66750/1
Sleep Mode
Setting the sleep mode bit (SLP) to 1 puts the HD66750/1 in the sleep mode, where the device stops all
internal display operations, thus reducing current consumption. Specifically, LCD operation is completely
halted. Here, all the SEG (SEG1 to SEG128) and COM (COM1 to COM128) pins output the GND level,
resulting in no display. If the AP1-0 bits in the power control register are set to 00 in the sleep mode, the
LCD drive power supply can be turned off, reducing the total current consumption of the LCD module.
Table 27 Comparison of Sleep Mode and Standby Mode
Function
LCD control
R-C oscillation circuit
Sleep Mode (SLP = 1)
Turned off
Operates normally
Standby Mode (STB = 1)
Turned off
Operation stopped
Standby Mode
Setting the standby mode bit (STB) to 1 puts the HD66750/1 in the standby mode, where the device stops
completely, halting all internal operations including the R-C oscillation circuit, thus further reducing
current consumption compared to that in the sleep mode. Specifically, all the SEG (SEG1 to SEG128) and
COM (COM1 to COM128) pins for the multiplexing drive output the GND level, resulting in no display. If
the AP1-0 bits are set to 00 in the standby mode, the LCD drive power supply can be turned off.
During the standby mode, no instructions can be accepted other than the start-oscillation instruction. To
cancel the standby mode, issue the start-oscillation instruction to stabilize R-C oscillation before setting the
STB bit to 0.
Turn off the LCD power supply: AP1 to 0 = 00
Set standby mode: STB = 1
Standby mode
Issue the start-oscillation instruction
Wait at least 10 ms
Cancel standby mode: STB = 0
Turn on the LCD power supply: AP1 to 0 = 01 / 10 / 11
Figure 55 Procedure for Setting and Canceling Standby Mode
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