LMT028DHHFWL-NBN
LCD Module User Manual
Prepared by:
Checked by:
Approved by:
Wangxikuan
Date: 2019-05-08
Date:
Date:
Rev. Descriptions
Release Date
0.1
Preliminary new release
2018-03-15
0.2
Update description of /RD
2018-11-21
0.3
Update Terminal Functions
2019-05-08
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Table of Content
1. Basic Specifications .............................................................................................................. 3
1.1 Block Diagram ................................................................................................................................................................ 3
1.2 Terminal Functions ......................................................................................................................................................... 4
2. Absolute Maximum Ratings .................................................................................................. 5
3. Electrical Characteristics ...................................................................................................... 5
3.1 DC Characteristics ......................................................................................................................................................... 5
3.2 AC Characteristics ......................................................................................................................................................... 6
3.3 Backlight control Timing ................................................................................................................................................. 7
3.4 Reset Timing .................................................................................................................................................................. 7
4. Functions ............................................................................................................................... 8
4.1 Display Commands ......................................................................................................................................................... 8
4.2 Power off the LCD Module ............................................................................................................................................ 13
4.3 Refreshing The LCD Module ......................................................................................................................................... 13
5. Optical Characteristics ........................................................................................................ 13
6. Design and Handling Precaution ........................................................................................ 15
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1. Basic Specifications
Screen Size(Diagonal) :
2.8”
Color Depth:
65k colors
Number of dots :
320 x 240(RGB)
Active Area :
57.6x43.2 mm
Dot Pitch :
0.18x0.18 mm
Display Technology :
a-Si TFT active matrix
Display Mode :
Transmissive / Positive
Pixel Configuration :
RGB Stripe
Viewing Direction :
9H (*1) (gray scale inverse)
3H (*2)
Polarizer Surface Treatment:
Glare
Backlight Type:
LEDs
Outline Dimension :
79.3 x 49.1 x 6.8(Max) mm (see dwg for details)
Operating Temperature :
-20 ~ +70°C
Storage Temperature :
-30 ~ +80°C
Note:
*1. For saturated color display content (eg. pure-red, pure-green, pure-blue, or pure-colors-combinations).
*2. For “color scales” display content.
*3. Color tone may slightly change by Temperature and Driving Condition.
1.1 Block Diagram
BLEN
Backlight Circuit
TFT Panel
320 × 240(RGB)
VDD
VSS
/RD, /WR, D0~D7
ST7789VI or equivalent
/CS, /RES,D/C,FMARK
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1.2 Terminal Functions
Pin No.
(K1)
Pin Name
I/O
Descriptions
1
VSS
2
VSS
P
Negative power supply,0V
Backlight enable
3
BLEN
I
BLEN = H: turn on Backlight
BLEN = L: turn off Backlight
4
VDD
5
VDD
P
Positive power supply
6
/RD
I
Read enable input, active low
7
/WR
I
Write enable input, active low
Register Select
8
D/C
I
D/C=H, Transferring the Display Data
D/C = L, Transferring the Control Data
Chip Select
9
/CS
I
/CS=L, enable access to the LCD module
/CS=H, disable access to the LCD module
10
D0
I/O
Data Input
:
:
:
:
17
D7
I/O
Data Input
Reset signal
18
/RES
I
/RES = L, Initialization is executed
/RES = H, Normal running.
19
FMARK
O
Displaying Timing Frame Signal
20~28
NC
-
-
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2. Absolute Maximum Ratings
VDD =5V, VSS=0V, T OP =25  C
Items
Symbol
Min.
Max.
Unit Condition
Supply Voltage
VDD
-0.3
+5.5
V
VSS= 0V
Input Voltage
V IN
-0.3
+4.6
V
VSS = 0V
Operating Temperature
T OP
-20
+70
 C
No Condensation
Storage Temperature
T ST
-30
+80
 C
No Condensation
Cautions:
Any Stresses exceeding the Absolute Maximum Ratings may cause substantial damage to the device. Functional
operation of this device at other conditions beyond those listed in the specification is not implied and prolonged exposure
to extreme conditions may affect device reliability.
3. Electrical Characteristics
3.1 DC Characteristics
VDD=5V, VSS=0V, T OP =25  C
Items
Symbol
MIN.
TYP.
MAX.
Unit Condition /
Application Pin
Operating Voltage
VDD
4.8
5.0
5.2
V
VDD
IOVDD
1.65
3.0
3.6
V
IOVDD
Input High Voltage
V IH
0.7* IOVDD
-
IOVDD
V
/RES,D0~D7,/CS
Input Low Voltage
V IL
0
-
0.3* IOVDD
V
/RD,/WR,BLEN,D/C
Operating Current
I DD
-
74.5
85
mA Backlight are ON
I DD
-
6.25
16
mA Backlight are OFF
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3.2 AC Characteristics
8080 Mode System Bus Timing
VDD =5V, VSS=0V, T OP =25  C
Signal
Symbo
Spec.
l
Parameter
Min.
Max.
Unit
Description
Address setup time
5
-
D/C
T AST
ns
-
T AHT
Address hole time(Write/Read)
13
-
T CHW
Chip select “H” pulse width
5
-
T CS
Chip select setup time(Write)
20
-
Chip select setup time(Read ID)
60
-
/CS
T RCS
ns
-
T RCSFM Chip select setup time(Read FM)
460
T CSF
Chip select wait time(Write/Read)
13
T CSH
Chip select hold time
13
T WC
Write cycle
86
-
/WR
T WRH Control pulse “H” duration
20
-
ns
-
T WRL Control pulse “L” duration
20
-
T DST
Data setup time
13
-
For maximum
T DHT
Data hold time
13
-
CL=30pF
DB[7:0]
T RAT
Read access time(ID)
-
52
ns
For minimum
CL=8pF
T RATFM Read access time(FM)
-
442
T ODH
Ouput disable time
14
104
T RC
Read cycle(ID)
208
/RD(ID)
T RDH
Control pulse “H” duration(ID)
120
When read ID data
T RDL
Control pulse “H” duration(ID)
60
ns
T RCFM Read cycle(FM)
585
/RD(FM)
When read from
T RDHFM Control pulse “H” duration(FM)
120
frame memory
T RDLFM Control pulse “H” duration(FM)
460
Note:
*1. Input signal rise/fall time should be less than 15ns .
*2. All timing is using 20% and 80% of VDD as the reference.
*3. Please refer to ST7789VI datasheet for details
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3.3 Backlight control Timing
VDD=5V, VSS=0V, T OP =25  C
Signal
Symbol
Parameter
Spec.
Min. Typ Max.
Unit Description
t HI
Time Delay between Steps
2
-
-
us H: 3.3V
BLEN
t LO
CTRL LOW Time for Dimming
1
-
250
us L: 0V
t SD
CTRL LOW ,shutdown Pulse Whidth
2
-
-
ms
Note: For basic ON/OFF function, please beware of minimum pulse width.
Register BLEN timing
3.4 Reset Timing
VDD =5V, VSS=0V, T OP =25  C
Item
Symbol
MIN.
TYP.
MAX.
Unit
Reset LOW pulse width
t RW
10
-
-
us
Reset time
T RT
-
-
170
ms
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4. Functions
4.1 Display Commands
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Notes:
1. There will be no abnormal visible effects on the display when S/W or H/W Reset are applied.
2.
Please refer to ST7789s datasheet for details
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4.2 Power off the LCD Module
It recommends that enter Sleep Mode before power off the LCD module.
4.3 Refreshing The LCD Module
It recommends that the operating modes and display contents be refreshed periodically to prevent
the effect of unexpected noise.
5. Optical Characteristics
Item
Symbol
Condition
MIN.
TYP.
MAX.
UNIT
Note.
Φ=90 o
50
60
-
Viewing angle
Φ=270 o
50
60
-
(CR ≥ 10)
degree
Note 1,6
Φ=180 o
40
50
-
Φ=0 o
50
60
-
Φ=0 o
Contrast ratio
CR
300
500
-
-
Note 3
θ=0 o
T on
Φ=0 o
msec
Response Time
-
30
50
Note 4
T off
θ=0 o
msec
X
0.55
0.60
0.65
Red
Y
0.30
0.35
0.40
X
Backlight
0.27
0.32
0.37
Green
Y
is on
0.56
0.61
0.66
Chromaticlty
Φ=0 o
X
0.09
0.14
0.19
Note 1,5
Blue
θ=0 o
Y
0.05
0.09
0.15
X
0.26
0.29
0.32
White
Y
0.28
0.31
0.34
NTSC Ratio
S
45
65
-
%
Luminance
L
Φ=0 o
200
250
-
cd/m 2
Note 1,6
Luminance uniformity
U
θ=0 o
80
-
-
%
Note 1,6
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Note 1:
Note 2:
The data are measured after LEDs are turned on for 5 minutes.
The definition of viewing angle:
LCM displays full white. The brightness is the average value of 9 Refer to the graph below marked by θ and Ф
measured spots. Measurement equipment PR-705
Measuring condition:
- Measuring surroundings: Dark room
- Measuring temperature: Ta=25 ℃ .
- Adjust operating voltage to get optimum contrast at
the center of the display.
Note 3:
The definition of contrast ratio (Test LCM using PR-705):
Note 4:
Contrast
Luminance When LCD is at “White” state
Definition of Response time. (Test LCD using DMS501):
Ratio(CR)
=
Luminance When LCD is at “Black” state
The output signals of photo detector are measured
(Contrast Ratio is measured in optimum common electrode
when the input signals are changed from
voltage)
“black” to “white”(falling time)
and from “white” to “black”(rising time), respectively.
The response time is defined as
the time interval between the 10% and 90% of amplitudes.Refer to
figure as below.
Note 5:
Note 6:
Definition of Color of CIE1931 Coordinate and NTSC Ratio.
The luminance uniformity is calculated by using following formula.
△ Bp = Bp (Min.) / Bp (Max.)×100 (%)
Color gamut:
Bp (Max.) = Maximum brightness in 9 measured spots
Area of RGB triangle
S=
X100%
Bp (Min.) = Minimum brightness in 9 measured spots .
Area of NTSC triangle
Note 7:
Measured the luminance of white state at center point
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6. Design and Handling Precaution
Please refer to "LCD-Module-Design-Handling-Precaution.pdf".
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