Thanks Tom!

I did as you suggested and lifted the pin on the RS232 chip. Both displays work fine now with my original 10K pullups.

Is there any reason why you recomend 4K7?

If we get the order we are expecting we will need more displays - is there any way we can guarantee to get ones we don't ...

OK, I've sort of fixed it but I'm not happy with the solution.

It seems to be the pull up resistors on the I2C lines.

My origional design used 10K resistors on both SDA and SCL. This worked fine with various I2C devices including the LCD0821.

I read the posts here regarding I2C and then tried ...

I have checked the LK202-25 boards with a meter and the SDL / SDK lines are connected to the correct pins on the 16F877 PIC .... I'm suspecting the firmware is incorrect??

The LK202-25s are R2.2
One has a sticker 2815-05M11, the other 2814-05M11

One has 0539/6 on the board, the other 0538/5

Mark.

Hi. I've just bought two LK202-25 s and can't get either of them to talk via I2C. I have a device that uses a PIC 18F452 and has an RTC and a EEPROM on board using the I2C interface.

I also have a LCD0821 rev 1.4.

I have been using the LCD0821 successfully and have not modified my code.

I have ...