Hello everyone, I am running into some inconsistencies when addressing I2C for writing strings to LCD screens. The LCD is from NHD and its data sheet can be found here. Below I have listed a list of Hex commands from the datasheet and I have successfully communicated with one LCD. I am now attempting to use the Hex commands found in that Datasheet to change its address to something other than the 7-bit default which is 0x28. I also made sure the LSB was 0 just as the LCD datasheet states. I have been trying to use address 0x2A, which is 00101010 in binary. This VI is suppose to change the address to 0x2A then display the I2C address on the screen. It does this successfully. Then when I go to run the VI addressed to the new address I get error 301742. Which just states the slave did not acknowledge an address and direction bit from the master. So I just need some guidance on correctly changing an I2C address. I will have 12 screens to communicate with at once. Also, I unfortunately am unable to transfer my VI to my network connected desktop so I have done my best to recreate it and attach it below.

Do you know if the LCD screen can remember its address after a power cycle? I think it does not have an EEPROM to remember the programmed address when power cycled.

LabVIEW

I2C Addressing with USB-8452

Solved!

Author

I found the issue and your comment gave me the idea to try it. After changing the address with my VI. I disconnected the LCD then repowered and it wrote with the new address.

Thank you!