sch,pcb,gerber file-->https://gitee.com/fiftyhz/BI1IZF/tree/m ... 74_HD44780
you can DIY PCB,Of course you can also buy the PCF8574 module.
- 1. Connect PCF8574 to Raspberry,VCC to VCC, SDA to SDA, SCL to SCL, GND to GND.The backlight cannot be controlled by PCF8574,
it needs to be connected separately,Please check the schematic.
- 2. Determine the I2C address,use
Code: Select all
i2cdetect -y 1
- 3. set MMDVM Display Type is HD44780 and save
- 4. check configuration-Expert-MMDVMHost-HD44780 config,if you use pwm,change pwn 1,Apply Changes
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- Normally, the screen will display, if there is no display, try to adjust the screen contrast
- If you buy a PCF8574 module, you must check the connection between the module and HD44780. It must be the following, is very important
- If you use PWM ,connection RPI Pin 32(GPIO pin 12,Wiring Pi pin 26) to HD44780 Pin15,Pin16 to GND,RPI output current can drive the backlight, of course you can use a triode
If you do not use PCF8574, you also need to compile the file->https://github.com/g4klx/MMDVMHost/blob ... ME.HD44780
I can answer all questions about HD44780
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BI1IZF