HT1647A(2009) Ver la hoja de datos (PDF) - Holtek Semiconductor
Número de pieza
componentes Descripción
Lista de partido
HT1647A Datasheet PDF : 19 Pages
| |||
PATENTED
HT1647A
Write Data Mapping to RAM for Pad Option
OP1
Pad Option
OP2
OP3
Level Selected
0
0
Level2 (1,0)
Level3 (0,1)
0
0
1
(Select D2
and D0)
1
0
Level4 (0,0)
Level3 (0,1)
Level2 (1,0)
Level1 (1,1)
1
1
Level4 (0,0)
Level1 (1,1)
0
0
Level3 (0,1)
Level2 (1,0)
1
0
1
(Select D3
and D1)
1
0
Level4 (0,0)
Level2 (1,0)
Level3 (0,1)
Level1 (1,1)
1
1
Level4 (0,0)
Level1 (1,1)
RAM Data
Note
0
Level1 and Level4 are not used
1
0
Level1 and Level2 are not used
1
0
Level3 and Level4 are not used
1
0
Level2 and Level3 are not used
1
0
Level1 and Level4 are not used
1
0
Level1 and Level3 are not used
1
0
Level2 and Level4 are not used
1
0
Level2 and Level3 are not used
1
Note: OP1 is used to select D3, D1 or D2, D0.
OP2 and OP3 are used to select two of four level gray scale.
The default value of OP1, OP2 and OP3 are (0,1,1).
Gray Scale Level Decision
HT1647A uses PWM technique to provide gray scale
display and only two of four level gray scale can be dis-
played simultaneously by setting OP1~OP3 pads. OP1
is used to select D3, D1 or D2, D0 and OP2 and OP3 are
used to select two of four level gray scale. The four level
gray scale are defined below table ²RAM Data Defined
Gray Scale Level². MCU write two bits data and only
one bit data is written to internal display RAM. The
OP1~OP3 pads setting is shown as following table
²Write Data Mapping to RAM for Pad Option².
RAM Data Code
(D3, D2) or (D1, D0)
Choice Gray Scale Level
(1, 1)
Level 1
(1, 0)
Level 2
(0, 1)
Level 3
(0, 0)
Level 4
RAM Data Defined Gray Scale Level
Frame Frequency
HT1647A provides two kinds of frame frequency option
by command code; 89Hz and 170Hz respectively.
FRAME 89Hz provides 89Hz frame frequency and ac-
tive segment signal width can be divided into 24 sec-
tions concurrently. FRAME 170Hz provides 170Hz
frame frequency and active segment signal width can be
divided into 13 sections concurrently. The 24 sections
display a particularly gray scale more than the 13 sec-
tions by PWM data. The default is FRAME 89Hz.
Gray Scale Display
If the user choose 89Hz frame frequency, a max. of 24
sections can be programmed to suit a satisfactory gray
scale in every level. Similarly, if the user choose 170Hz
frame frequency, a max. of 13 sections can be pro-
grammed to suit a satisfactory gray scale in every level.
HT1647A provides 5-bit PWM data to control the length
of the section. In other words, a max. Of 24 gray scales
are generated by 5-bit binary PWM data. At FRAME
89Hz mode, the HT1647A only provides a max. of 24
adjustable gray scales although 32 is the expressed
max. value by 5 bits binary code. When 5 bits binary
code value is more than 23, the PWM control circuit uni-
formly regards 23. To increase PWM data indicates to
increase the length of the active segment signal. The
varied length of the active segment signal displays var-
ied gray scale in TN-type, STN-type LCDs (refer to table
1). Similarly, it displays varied color in ECB-type LCDs.
The color display is derived from ECB-type LCD specifi-
cation. At FRAME 170Hz mode, the HT1647A only pro-
vides a max. of 13 adjustable gray scales although 32 is
the expressed max. value by 5 bits binary code. When
the 5 bits binary code value is more than 12, the PWM
control circuit uniformly regards 12. The user must ap-
point four kinds of PWM data to four kinds of different
gray scale level by commanding PWM data (refer to ta-
ble 2).
Rev. 1.20
9
June 22, 2009
Share Link: 