The input voltage of e-paper is generally 2.3~3.6V, 3.3V is recommended. In addition, the low voltage should not be lower than 2.5V to avoid affecting the display effect of e-paper. Please add boost test points, otherwise it will be inconvenient to test the circuit after the prototype is made, and product maintenance in the future will also be a problem.

It is recommended to select a 47uH wire-wound inductor. For MOS transistors, Si1304BDL or Si1308EDL are recommended. If these two are really hard to buy, AO3400 can be selected as a substitute. The diode needs to select a Schottky diode equivalent to MBR0530 parameters, and the switching frequency should meet the actual requirements. The theoretical capacitance withstand voltage value needs to be 50V, and 25V can also be used instead in actual design.

SPI serial e-paper selects 24PIN FPC socket with top contact or top-bottom contact, pin pitch 0.5mm. The length of FPC cable is recommended not to exceed 20cm. The longer the FPC cable, the more prone to transmission data errors.

The GDR frequency is generally set by software, and the switching frequency is generally below 100kHz. The frequency cannot be modified by default for e-paper with built-in OTP version. We do not recommend using 5V directly. When the MCU power supply is 5V, the IO is 5V, because the e-paper working at 5V for a long time is easy to burn out the IC.

The analog SPI interface is adopted in the e-paper sample program. When transplanting the software, users only need to change the IO port. The e-paper supports hardware SPI, but the MISO pin needs to be idle. The final connection method is MOSI--SDIN, SCLK--SCLK, and other IO ports can be customized.

If the MOS transistor heats up, please check whether there is crosstalk in the peripheral circuit leading to abnormal conduction of the MOS transistor. The breakdown of the MOS transistor is mainly caused by the reverse of the positive voltage isolation diode, leading to the breakdown caused by the positive high voltage backflow. Please check whether the isolation diode in the driver circuit is soldered reversely.

It is recommended to use MiniGUI, which completely solves the problem that the MCU RAM is small and GUI display cannot be realized.

When the e-paper is not connected, the boost circuit and GDR of the driver are invalid.

The opening of the e-paper boost circuit is controlled by a fixed register. Only when the MCU sends a command to turn on the boost switch to the e-paper IC, the boost circuit can work normally.

The BUSY pin can be omitted, but it is necessary to use software delay to simulate the actual state of the BUSY pin. The delay time should be longer than the refresh time to ensure that the e-paper is refreshed within the effective time. Too short delay time will affect the actual refresh display.

If the BUSY pin of e-paper is always busy, first confirm that the BUSY is set to pull-up input mode during initialization, then check the IO port level. For example, the normal e-paper driver IO is 3.3V, while Arduino defaults to 5V, which may cause this phenomenon. If UC series e-paper is used, the 0x71 command can be cancelled in the busy judgment function, which does not affect the function judgment of the BUSY pin.

Stop the code at the 0x04 command during initialization, then use a multimeter to test the voltage of PREVGH and PREVGL.

Since the backlight requires a large current, it is recommended that the customer supply power to the backlight separately to avoid affecting the normal display of the e-paper.

We recommend that the customer place the mobile phone about 2mm above the device. Too large distance may lead to insufficient field strength energy and failure to drive the display.

It may be that the direction of the diode welded by the customer is wrong, causing the MOS to be in a short-circuit state all the time.

It is generally recommended that the customer's withstand voltage value is above 25V.

The display command is not executed, or the IC may be defective.

In case of screen cracking or breaking, if the e-paper has a display picture, it is the customer's responsibility; if it is a pure white picture, it is caused by transportation.

We normally recommend customers to select standard components in the specification sheet. If replacement is needed, selection can be made with reference to the specification parameters of standard components.

The touch screen is generally an IIC interface, which can be directly connected to the MCU. If the MCU IO used does not support pull-up operation, an additional pull-up resistor needs to be added.

The front light generally adjusts the current through the circuit. Customers need to design an adjustable resistor to adjust the brightness of the front light, or customers can drive it with a dedicated current source.

Flash and font library signals share a set of SPI interfaces with e-paper. The difference is that each device has an independent CS pin, and the driving function of different devices can be switched by controlling the CS pin.

This chip is a traditional font library chip, which supports GB2312 standard national font library and commonly used ASCII code display.

Improper selection of MOS transistor model leads to failure of boost circuit to work normally.

At present, the TCON driver of Eink parallel port e-paper is mainly IT8951 produced by ITE company, and some e-book customers use chips from RK company, which have built-in TCON functions.

Our STM32, ESP32, ESP8266 and Arduino development platforms are all equipped with CH340G as USB to serial chip, which can directly connect PC and development board with USB cable for serial operation and download. STM32 development board can short-circuit the corresponding Boot interface: P12 for serial download through short-circuit cap. The software used for download is FLYMCU, and the download method is similar to C51 (disconnect P12 short-circuit cap after download)

Our STM32, ESP32, ESP8266 and Arduino development platforms all support measuring onboard power consumption and e-paper power consumption

Our STM32, ESP32, ESP8266 and Arduino development platforms lead out all pins of the MCU. Users can completely connect other peripherals through this development board for design and development of other products. In addition, the main board can drive multiple groups of adapter boards, and the interface has been reserved.

Arduino, ESP32, ESP8266 development boards can directly drive touch screens. When using, you need to customize IO ports, generally including SDA, SCL, RST, INT. DESPI-C03 is equipped with touch screen and e-paper drive interface.

Since some touch screen ICs and e-paper ICs have conflicts in default levels, making it impossible to share a set of IO ports, it is necessary to test related functions separately during testing.

The only difference between 3-wire and 4-wire is the D/C pin part. If 3-wire SPI is used, the D/C pin needs to be connected to GND, then the D/C function is realized by software part, and the D/C function is added each time data is transmitted.

It may be that the customer has not configured the chip model normally, resulting in the mismatch between the current chip capacity and the actual one.

ESP32-FTS02 is an upgraded version of ESP32-T01. In addition to supporting the basic touch screen interface, it also supports front light interface, Raspberry Pi interface, SD card expansion interface, etc., which is convenient for users to develop and test.

The SPI part of ESP32-L development board uses high-speed hardware SPI, and FLASH and font library chips are added at the same time.

This chip is a reserved chip, and its main function is to provide common font libraries for customers' reference design.

NRF series MCU generally has 51 or ARM core. This kind of MCU can control IO individually. In actual use, e-paper can be driven by simulating SPI.

These two types of e-paper driver boards are compatible. The difference is the pin definition and FPC pitch of e-paper. In addition, the waveform built in FLASH also needs to be replaced.

The driver board of this e-paper is driven by four IT8951 chips. Before actually importing pictures, it is necessary to create an empty Temp folder in the root directory of computer C drive, which is mainly used for host computer picture segmentation.