16x2 LCD is getting blank in between the operation once in a while, then system restart required

Question

I am using stm32g070rbt6 controller (32Mhz) and communicating with 16x2 LCD in 4-bit mode,

Issue we are getting is in between the operation once in may be 2 to 3 hours, all of sudden LCD will get blank continuously, it'll come back to normal only after restarting the machine.

Below points for your reference,

1.We are using for motor application (Coffee vending machine)

2.Cable length is 1meter from controller to lcd display.

3.16x2 LCD is JHD162A

4.LCD is 5V, but from controller to LCD the data lines are 3.3V because our controller will provide 3.3V.

5. At 5V regulator output is connected with 470uF, input at regulator is 100uF, LCD connector on the board is 10uf.

At LCD side, 220uF capacitor is connected and 0.1uF capacitor is connected to EN, RS and 4 data lines. There was huge improvement after adding the above capacitors. Earlier display was going off in every 5 to 10mins itself.

I'm stuck to resolve this issue, request your support to resolve this issue.

Thanks in Advance.

Regards,

Nikhil

S.Ma · Answer

Do you have the spec of the display ? Character based ? Pixel based ? how many bits per pixels ?

For character based, the memory to push by SPI is small like 128 bytes, so to avoid artifacts, I create a display RAM buffer in the MCU, the MCU can erase, printf, on the MCU Display RAM Page, then, when all is ready to be updated, the SPI command to erase and full refresh the screen page is done in a milisecond order.

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