Renesas SH7781 - Manual (Page 998)

19. Display Unit (DU)
Rev.1.00 Jan. 10, 2008 Page 968 of 1658
REJ09B0261-0100
19.6 Power-Down Sequence
When executing the power-down sequence by the following modes or functions, turn off the
display in advance.
1. Sleep mode
2. Deep sleep mode
3. Module standby
4. Change of frequency
5. Manual reset
Even when the display unit (DU) enters the power-down sequence, the register values are retained.
During a power-down sequence, do not access the display unit (DU).
19.6.1 Procedures before Executing the Power-Down Sequence
1. Display is turned off by setting both the DEN and DRES bits in DSYSR to 0.
2. Use the VBK bit in DSSR to confirm the next VBK flag (because the display is turned off with
the timing of VBK).
3. The display unit (DU) displays the data in DOOR before the display is turned off.
4. Execute the power-down sequence.
5. Display unit (DU) is turned off.
19.6.2 Resetting the Power-Down Sequence
1. Reset the power-down sequence and start the clock.
2. Make settings to turn the display on, with the DEN and DRES bits in DSYSR set to 1 and 0
respectively.