LCD1602 expansion board based on CH552T

The project has been posted to the Digital Home Forum!

https://www.mydigit.cn/forum.php?mod=viewthread&tid=150554&extra=

The LCD1602 expansion board based on CH552T can be used to test whether the LCD1602 is normal, or you can write your own program to communicate with the LCD1602 through UART or USB to save the number of IOs.

R1 and R2 are voltage dividing resistors that generate the LCD1602 bias voltage. If the VO pin of the LCD1602 used already has an internal pull-up resistor, there is no need to solder R1. Please adjust the resistance values ​​of R1 and R2 according to the actual situation to make the LCD1602 display clear and without residual images. R3 is a resistor that adjusts the brightness of the LCD backlight. Please adjust the resistance of R3 according to the actual situation so that the backlight of the LCD1602 is at the appropriate brightness.

This design uses 5V power supply. If you bring your own MicroUSB data cable, you can power the circuit through the USB interface. At the same time, since the CH552T has a USB slave function and supports USB downloading programs, this USB interface can also be directly used to download programs, or the USB function can be configured in the program to directly output debugging information to the virtual serial port.

This design has a custom function button (connected to INT0), which reserves a download button and a reset button to facilitate downloading the program through USB without purchasing a separate USB to TTL board.

This design has a power indicator light and two custom function indicator lights (connected to P3.0 and P3.1), which can display the communication status of the UART and can also be used as indicators for other functions when the UART is not used.

This design introduces two IOs, P3.0 and P3.1, and is equipped with a bidirectional level conversion circuit. You can choose the 3.3V level or the 5V level. The 3.3V power supply is generated by CH552T, saving one LDO and saving costs. These two IOs can be configured as UART, and with the level conversion circuit, they can communicate with other 3.3V or 5V logic level devices. It can also be configured as a normal GPIO to communicate with other devices through software simulation of the I2C protocol.

The attachment provides two routines. The compressed package is a complete Keil project, which can be opened using Keil5. The hex format file is a compiled program and can be burned directly with WCHISPTool.

Routine LCD1602 is a routine that allows LCD1602 to scroll and display. It can simply test whether LCD1602 is working normally.

The routine SystemViewer is a routine that allows AIDA64 to output system information and display it to LCD1602 through the serial port. You can use it by connecting it to the computer via USB, and just install the CH340 driver.

Please note: AIDA64 only supports COM1~COM19. If the default port number exceeds 19, please modify it in the device manager. Modification method: Right-click CH340 in the port in the device manager, select Properties, click Advanced on the Port Settings tab, and modify the port number.

The configuration method of AIDA64 is shown in the figure below. The first grid on the first line of each page can be identified if it is $.