3.8-inch HDMI screen with TF card dual-card dual-reading function

1. Product Introduction
Low-cost HDMI portable display, 3.8-inch 480X800 resolution MVA screen; with card reader function, supports dual TF card dual reading.
(Note: The advantages of MVA screen are high contrast, rich display details, and more eye-catching; but compared with IPS screen, the visibility is smaller.)
2. Application Scenario
DIY a very small and mini external display screen for computers, mobile phones, etc. to satisfy the fun of DIY.
The display has a card reader function, supports dual TF card dual reading, and can be used as a card reader.
3. Product Overview
HDMI screen function:
Based on LT8619C, HDMI to RGB drive LCD screen display image, refresh rate 60Hz.
Onboard left and right dual speakers FS-1540, based on CS4344 and APA2068 to realize HDMI audio external.
Card reader function:
Based on GL3224 to realize dual TF card dual reading function, theoretical write speed 100MB/S (actual depends on TF card).
Based on VL160 to realize TYPE-C positive and negative insertion function.
4. Product parameters
Screen: 3.8-inch 480X800 resolution MVA screen, driver IC is
Interface:
HDMI-C Type interface (mini HDMI interface) *1
TYPE-C interface *1
Self-flying TF card holder *2
Main control: STC8H8K64U-TSSOP20
Speaker: FS-1540 *2
Button: Side sticker *3 (support volume adjustment, brightness adjustment, subsequent firmware update)
Indicator: TF card insertion indicator, HDMI working status indicator
 
PCB rendering:
PCB schematic:
Shell assembly drawing:
5. Instructions for use
According to the schematic diagram, the PCB is soldered. The system is powered by a 5V power supply (can be powered by an HDMI cable or a TYPE-C cable alone). The HDMI part is powered by two 1117 linear step-down outputs of 3.3V and 1.8V, and the card reader part uses the LDO inside the GL3224 chip to output 3.3V and 1.2V.
In order to realize the HDMI screen function and card reader function of the board, the firmware of the two parts needs to be burned separately after the board is soldered.
First is the HDMI screen part. Prepare a USB to TTL module, connect its RX, TX, and GND to the 4P pin header or 4P1.25mm wire-to-wire connector on the board, use STC-ISP software to burn the firmware, and the cold start part is achieved by plugging the TYPE-C cable to power on the system.
Then comes the card reader part. Connect the board to the computer via the TYPE-C cable, open the software, and the device and firmware will be identified. Select the firmware to be upgraded and click to upgrade.
6. The production cost
does not include the 3D printed shell and PCB, and the cost of components is nearly 120 yuan.
7. Remarks:
The screen connector AXT350124 (50PIN)
is planned to be updated in the future: three buttons to adjust the volume and brightness, so stay tuned.
Screen purchase link: See the attachment for the link.
Communication group: 227055619
B station UP: Mount and Blade Financial Advisor, you can come to my B station workshop to shoot the finished product
(Note: only the reading and writing functions have been verified to be normal, and the reading and writing speeds are also affected by the TF card itself)