EM65570
68COM/ 98SEG 65K Color STN LCD Driver
8.2.16 Electronic Volume Register
D7 D6 D5 D4 D3 D2 D1 D0
DV3 DV2 DV1 DV0
CSB RS RDB WRB RE2 RE1 RE0
0
1
0
1
0
1
1
0
0
0
1
(Read address: 5H)
D7 D6 D5 D4 D3 D2 D1 D0
DV6 DV5 DV4
CSB RS RDB WRB RE2 RE1 RE0
0
1
1
0
*
0
1
1
0
0
0
1
* Don’tCare
(Read address: 6H)
(At the time of reset: {DV6~DV0} = 00H)
The DV register controls the VBA voltage.
DV6
DV5
DV4
DV3
DV2
DV1
DV0
Output Voltage
0
0
1
1
0
0
0
0
0
0
0
0
0
1
32
33
：
：
95
96
：
：
1
1
1
0
1
1
0
1
0
1
0
1
0
0
The output voltage at VBA is specified by the following equation:
VBA = (1+ (M+offset)/381) * VREF
Where: M: DV register value
offset: CV register value
VREF: temperature compensation output voltage
The VBA range is from 1.5V to 2V at 25°C.
The LCD drive voltage V0 is determined by the VBA level and the RM register value as
shown in the following equation:
V0 = VBA * N
N: RM register value
NOTE
When using EEPROM function (CV) to tune VBA offset, limit DV value to 32~96 to
prevent getting incorrect VBA value due to (M+offset) overflow or underflow.
In order to prevent transient voltage generation when an electronic volume code is set,
design the circuit in such a way that the set value is not reflected as a level immediately
after the upper bits (DV6-DV4) of the set electronic code. The set value becomes valid
only when the lower bits (DV3-DV0) of the electronic control volume code have also
been set.
NOTE
When writing code to set the electronic volume register, you must set DV6~DV4 first,
then followed by DV3~DV0 setting.
Product Specification (V1.0) 09.05.2005
(This specification is subject to change without further notice)
• 71
ELAN [ ELAN MICROELECTRONICS CORP ]
