LCDWIKI MSP2833 2.8inch IPS SPI Module User Manual
- June 14, 2024
- LCDWIKI
Table of Contents
LCDWIKI MSP2833 2.8inch IPS SPI Module
Resource Description
The resource directory is shown in the following figure:
| Directory | Content Description |
|---|
1-Demo
| Contains sample programs and usage
instructions for each MCU
2-Specification
| Including LCD screen specifications and product
specifications
3-Structure_Diagram
| Including touch screen size structure documents, product size structure documents
4-Driver- IC- Data- Sheet
| Including LCD screen driver IC Datasheet and Touch Screen driver IC Datasheet
5-Schematic
| Including product hardware schematic diagram, LCD Altium component diagram,
and PCB packaging
6-User Manual| Contains product user instructions document
7-Character&Picture_Molding_Tool
| Contains image extraction software, character extraction software, and software usage instructions. The image and text display tests in the sample program require the use of these two
software for mold taking.
Interface Description
The interface on the back of the module is shown in the following figure
:
Working principle
Introduction to ILI9341 Controller
The ILI9341 controller supports a maximum resolution of 240*320 and a
172800-byte GRAM. It also supports 8-bit, 9-bit, 16-bit, and 18-bit parallel
port data buses. It also supports 3-wire and 4-wire SPI serial ports. Since
parallel control requires a large number of IO ports, the most common one is
SPI serial port control. The ILI9341 also supports 65K, 262K RGB color
display, display color is very rich, while supporting rotating display and
scroll display and video playback, display in a variety of ways. The ILI9341
controller uses 16bit (RGB565) to control a pixel display, so it can display
up to 65K colors per pixel. The pixel address setting is performed in the
order of rows and columns, and the incrementing and decreasing direction is
determined by the scanning mode. The ILI9341 display method is performed by
setting the address and then setting the color value.
Introduction to SPI Communication Protocol
The writing mode timing of the 4 4-wire SPI bus is shown in the following
figure:
CSX is a slave chip selection, and the chip will only be enabled when CSX is
at low power level. D/CX is the data/command control pin of the chip. When DCX
is writing commands at low levels, data is written at high levels SCL is the
SPI bus clock, with each rising edge transmitting 1 bit of data; SDA is the
data transmitted by SPI, which transmits 8 bits of data at once. The data
format is shown in the following figure:
High bit first, transmit first. For SPI communication, data has a transmission timing, with a combination of real-time clock phase (CPHA) and clock polarity (CPOL): The level of CPOL determines the idle state level of the serial synchronous clock, with CPOL=0, indicating a low level. CPOL pair transmission protocol The discussion did not have much influence; The height of CPHA determines whether the serial synchronous clock collects data on the first or second clock jump edge, When CPHL=0, perform data collection at the first transition edge; The combination of these two forms four SPI communication methods, and SPI0 is commonly used in China, where CPHL=0 and CPOL=0
Hardware Description
6P capacitive touch screen FPC interface
P1 is a flip over FPC holder with a spacing of 6P 0.5mm, used to connect the 6P FPC cable of the capacitive touch screen and connect touch signals.
Power supply voltage stabilizing circuit
This circuit is used to stabilize the input voltage of the module, where VCC is the external input voltage, VCC3.3V is the module input voltage, and C1 is the bypass filter capacitor. VCC can be connected to 5V or 3.3V, and it is recommended to connect to 5V because only by connecting to 5V can VCC3.3 output 3.3V. If connected to 3.3V, VCC3.3 output voltage will be less than 3.3V, which will cause the backlight brightness of the LCD screen to darken.
SD card slot interface circuit
SD_ CARD1 is a Micro SD card slot for inserting Micro SD cards, making it easy to use SD card expansion functions. The SPI bus and LCD used are shared.
Backlight control circuit
R1 is reserved for compatibility with the J3Y control circuit, directly using a 0 ohm resistor. R2 is the backlight current limiting resistor, R7 is the pull-up resistor, and Q1 is the BSS138 N channel field-effect transistor. LED is the control signal, and LEDK is connected to the negative pole of the backlight. When the LED is suspended (without a control signal), due to R7 pull-up, the source of BSS138 is at a high level, with its gate and drain conducting, LEDK grounded, and the backlight circuit conducting, thus turning on the light. When the LED input is low, the source of BSS138 is low, its gate and drain are cut off, LDEK is suspended, and the backlight circuit is cut off, thus turning off the light; When the LED input is at a high level, the source of BSS138 is at a high level, its gate and drain are conductive, LDEK is grounded, and the backlight circuit is conductive, thus turning on the light;
Capacitor touch screen IIC signal level conversion circuit
R3, R4, R5 and R6 are pull-up resistor, and Q2 and Q3 are BSS138 N-channel FETs. CTP SDA、CTP IIC signal input from SCL main control terminal, 3V3 CTP SDA、3V3 CTP SCL is the converted IIC signal. The function of this circuit is to convert the 5V or 3.3V IIC signal input from the main control terminal into a 3.3V IIC signal, and then input it into the capacitive touch module (because the capacitive touch module can only receive 3.3V signals). It can also convert the 3.3V signal output from the capacitive touch module into a 5V signal and input it to the main control. The principle is (taking SDA as an example): the source of BSS138 is always at 3.3V level, and when CTP SDA is at low level, the drain of BSS138 is at level, the source voltage is higher than the drain, the gate and drain are conducting, and the gate is also at low level, 3V3 CTP SDA is a low level; When CTP SDA is at high level, with the drain 5V level of BSS138. The source voltage is lower than the drain, and the gate and drain are cut off. The gate is pulled up to 3.3V high level, with 3V3 CTP SDA is a high level. vice versa.
14P Header pin interface
J2 is 14P pin, R8 is the pull-up resistor of SD card CS pin. The 14P pin is used to connect to the main control, which can be directly inserted or connected through a DuPont cable. Because the SD card and LCD share the SPI bus, first pull up the CS pin of the SD card to disable its functions and avoid SPI bus device conflicts when the module is in use.
14P FPC interface circuit
P2 is the module 14P FPC cable interface, which can only be connected to the main control through the FPC cable.
Control signal level conversion circuit
U2 is a level conversion IC that converts between 5V and 3.3V. This circuit only uses the one one-way function of 5V to 3.3V, and the signals that the module needs to write are converted through this circuit.
18P LCD screen cable welding interface
QD3222 is a 18P pad with a spacing of 0.8mm. Used to weld the LCD so that it can receive signals from the main control.
Example program usage instructions
For specific instructions, please refer to the example program usage instructions document in the example program directory.
- A. Connect the display module to the main control board (directly plugin, use DuPont cable or FPC cable connection);
- B. Connect the main control board to the PC (it needs to be connected according to the download method) and power on the main control board;
- C. Modify, compile, and download sample programs;
- D. Check the display of the module and check if the program runs successfully;
Common tool software
The example program needs to display both Chinese and English, symbols, and
images, so it requires the use of mold-taking software. There are two types of
mold-taking software: Image2Lcd and PCtoLCD2002. Image2Lcd is used for color
image extraction, while PCtoLCD2002 is used for text or monochrome image
extraction. The PCtoLCD2002 mold-taking software is set as follows: Dot
Matrix Format Selection Yin Code Select row-by-row mode for mold-taking Select
the direction of the mold taking direction in the clockwise direction (with
the higher position in front) Output Number System Selection Hexadecimal
Number Custom Format Selection C51 Format 
The specific setting method can be found on the following webpage:
http://www.lcdwiki.com/Chinese_and_English_display_modulo_settings
The Image2Lcd mold taking software settings are shown in the following figure:
The Image2Lcd software needs to be set to scan horizontally, from left to right, from top to bottom, and with low bits in front.
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