ST7571 Sitronix Technology, ST7571 Datasheet - Page 52

• Manufacturer Part Number: ST7571
• Description: 4 Gray Scale Dot Matrix LCD Controller/Driver
• Manufacturer: Sitronix Technology

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ST7571
10.5 Referential Operation Flow : Power-OFF
By setting 0xA9, ST7571 will go into power save mode. The LCD driving outputs are fixed to VSS, built-in power circuits are
turned OFF and a discharge process starts.
Note:
1.
2.
3.
4.
5.
6.
7.
Ver 1.5a
Instruction Flow
After the built-in power circuits are turned OFF and
completely discharged, the power (VDD1 and VDD2)
can be removed.
t
t
It is NOT recommended to turn VDD1 OFF before VDD2. Without VDD1, the internal status cannot be guaranteed
and internal discharge-process maybe stopped. The un-discharged power maybe flows into COM/SEG output(s) and
the liquid crystal in panel maybe polarized.
IC will NOT be damaged if either VDD1 or VDD2 is OFF while another is ON.
The timing is dependent on panel loading and the external capacitor(s).
The timing in these figures is base on the condition that: LCD Panel Size = 1.8” and C=1uF.
When turning VDD2 OFF, the falling time should follow the specification:
300ms ≤ t
POFF
V2OFF
: Internal Power discharge time. => 250ms (max).
: Period between VDD1 and VDD2 OFF time. => 0 ms (min).
PFall
≤ 1sec
Fig. 28 Power off instruction flow
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2009/7/21