HD66727 Datasheet, PDF (33/97 Pages) Hitachi Semiconductor – Low-Power Dot-Matrix Liquid Crystal Display Controller/Driver with Key Scan Function

HD66727
Power Control
The power control instruction (Figure 13) includes the AMP, SLP, and STB bits.
AMP: When AMP = 1, each voltage follower for V1 to V5 pins and the booster are turned on. When AMP
= 0, current consumption can be reduced while character or segment display controlled by the multiplexing
drive method is not being used.
SLP: When SLP = 1, the HD66727 enters the sleep mode, where all the internal operations are halted
except for the annunciator display function, key scan function, and the R-C oscillator, thus reducing current
consumption. For details, refer to the Sleep Mode section. Only the following instructions can be executed
during the sleep mode.
1. Annunciator address (AAN) set
2. Annunciator data write
3. LED drive/general output port data write
4. Annunciator display on or off (DA = 1 or 0)
5. Voltage follower on or off (AMP = 1 or 0)
6. Standby mode set (STB = 1)
7. Sleep mode cancel (SLP = 0)
8. Key scan data (SD) read
9. Key scan interrupt generation enable/disable (IRE = 1 or 0)
10. Key scan cycle (KF) set
During the sleep mode, the other RAM data and instructions cannot be updated but they are retained.
STB: When STB = 1, the HD66727 enters the standby mode, where the device completely stops, halting all
the internal operations including the internal R-C oscillator and no external clock pulses are supplied.
However, annunciator display alone is available when the alternating signal for annunciator-driving signals
is supplied to the EXM pin. When the annunciator display is not needed, make sure to turn off display (DA
= 0). Normal key scanning is also halted in the standby mode. However, the HD66727 can detect four key
inputs connected with strobe signal KST0, thus generating the key scan interrupt (IRQ*). For details, refer
to the Standby Mode section and the Key Scan Interrupt section. Only the following instructions can be
executed during the standby mode.
1. Annunciator address (AAN) set
2. Annunciator data write
3. LED drive/general output port data write
4. Annunciator display on or off (DA = 1 or 0)
5. Voltage follower on or off (AMP = 1 or 0)
6. Start oscillator
7. Standby mode cancel (STB = 0)
8. Key scan interrupt generation enable/disable (IRE = 1 or 0)
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