I2C PCF8574 HD44780 Tutorial

All things relating to OLED Screen(s)
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BI1IZF
Posts: 2
Joined: Sat Feb 27, 2021 5:22 pm

I2C PCF8574 HD44780 Tutorial

Post by BI1IZF »

Open Source
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. :D
  • 2. 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.
  • 3. Determine the I2C address,use

    Code: Select all

    i2cdetect -y 1
this is my i2c addr
Image
  • clone MMDVMHost code to your RPI
  • make code

Code: Select all

sudo rpi-rw
sudo make clean
sudo make Makefile.Pi.PCF8574
wait......
  • install program,If the installation is successful,The date of the MMDVMHost file in /usr/local/bin is the latest

Code: Select all

make install
  • set MMDVM Display Type is HD44780 and save
  • check configuration-Expert-MMDVMHost-HD44780 config,if you use pwm,change pwn 1,Apply Changes
this is my config
Image
-----------------------------------------------------------------This is the dividing line---------------------------------------------------------
  • 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
Image
  • 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
Image
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

73
BI1IZF
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Last edited by BI1IZF on Thu Sep 09, 2021 1:58 pm, edited 1 time in total.
KE7FNS
Pi-Star Team
Posts: 2147
Joined: Wed Apr 17, 2019 11:11 pm

Re: I2C PCF8574 HD44780 Tutorial

Post by KE7FNS »

BI1IZF wrote: Wed Sep 08, 2021 2:11 pm
i2c is already enabled in Pi-Star.
BI1IZF wrote: Wed Sep 08, 2021 2:11 pm sudo make Makefile.Pi.PCF8574
You shouldn't have to build a custom MMDVMHost, Pi-Star is already configured to work with a HD44780.
If someones previous actions are any indication of their future actions, then I predict the deletion and removal of access will happen at any moment. 7-11-2020.

"07/13/20 This Website Has Been Taken Down" ... again :lol: and again
BI1IZF
Posts: 2
Joined: Sat Feb 27, 2021 5:22 pm

Re: I2C PCF8574 HD44780 Tutorial

Post by BI1IZF »

KE7FNS wrote: Wed Sep 08, 2021 5:05 pm
BI1IZF wrote: Wed Sep 08, 2021 2:11 pm
i2c is already enabled in Pi-Star.
BI1IZF wrote: Wed Sep 08, 2021 2:11 pm sudo make Makefile.Pi.PCF8574
You shouldn't have to build a custom MMDVMHost, Pi-Star is already configured to work with a HD44780.
Thank you for your answer
I saw in the G4KLX document that it needs to be compiled, but it is not needed, which makes the operation easier。 :lol:
KE7FNS
Pi-Star Team
Posts: 2147
Joined: Wed Apr 17, 2019 11:11 pm

Re: I2C PCF8574 HD44780 Tutorial

Post by KE7FNS »

BI1IZF wrote: Thu Sep 09, 2021 2:04 pm Thank you for your answer
I saw in the G4KLX document that it needs to be compiled, but it is not needed, which makes the operation easier。 :lol:
Compiling is needed for the MMDVMHost software, however Andy does a lot of the maintaining for Pi-Star users by doing the hard work himself (or in this case his server and scripts do it)

Pi-Star contains a custom MMDVMHost that has the ability to allow multiple configurations choices.

Also, whenever you update your custom MMDVMHost is going to get overwritten with Andys version, so I would suggest just using Pi-Star as it without modifications. The wiring should be identical, and when you selected the proper display it should work.
If someones previous actions are any indication of their future actions, then I predict the deletion and removal of access will happen at any moment. 7-11-2020.

"07/13/20 This Website Has Been Taken Down" ... again :lol: and again
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