I am trying to run LCD 16x2 hd44780 using STM32F4 discovery board, it showed the Data at first time after that nothing display on LCD. I tried all my possible ways pleas help me out.

[PKuma.12]

I create this project in Keil using cubemx.

 Keil-Mdk V-5 and STM32Cubemx

[PKuma.12]

Here is my cubemx pin configuration. I select pin D0-D3 at PORTB pin B12-B15 and pin D4-D7 at PORTD pin D8-D11. It is cubemx generated file so I dont think there is any error.

[PKuma.12]

I tried with 4-bit mode but it is not working in that mode also.

[Mon2]

Hi. My apologies, missed how you split up the 8 bit port on the first read.

Can you insert some small code to apply a logic HIGH or logic LOW onto say, Port Bit 0 of the LCD interface and then remain in a permanent loop.

Then check the logic level on this port pin using a meter - does it follow what was sent out by the CPU? Repeat for each of the port pins you are using to confirm that the ports are behaving as they should.

Then allow for the port pin to pulse @ 1Hz or something slow that can be monitored using a simple meter. Does the port pin toggle as it should?

These are good sanity checks.