BS85B12-3 HOLTEK [Holtek Semiconductor Inc], BS85B12-3 Datasheet - Page 149

• Manufacturer Part Number: BS85B12-3
• Description: Touch Key Flash Type 8-Bit MCU with LCD/LED Driver
• Manufacturer: HOLTEK [Holtek Semiconductor Inc]

BS85B12-3/BS85C20-3
Touch Key Flash MCU with LCD/LED Driver
Rev. 1.00
In Frame 0
In Frame 1
The accompanying waveform diagram shows a typical 1/3 Bias LCD waveform generated using the
application program. Note that the depiction of a 1 in the diagram illustrates an illuminated LCD
pixel. The COM signal polarity generated on pins SCOM0~SCOM3, whether 0 or 1, are generated
using the corresponding I/O data registers, which are bits PB0~PB3 in the PB register.
Note: The logical values shown in the diagram are the PB I/O register values, PB0~PB3.
A cyclic LCD waveform includes two frames, known as Frame 0 and Frame 1 for which the following
offers a functional explanation.
To select Frame 0 clear the FRAME bit to 0.
In frame 0, the COM signal output can have a value of VDD, or have a Vbias value of 1/3 VDD. The
SEG signal can have a value of VSS, or have a Vbias value of 2/3 VDD.
In frame 1, the COM signal output can have a value of VSS, have a Vbias value of 2/3 VDD. The SEG
signal can have a value of VDD have a Vbias value of 1/3 VDD.
1/3 Bias LCD Waveform
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February 1, 2011