I2C interface of GLK12232-25-SM

shenli7 · Post by **shenli7** » Fri Aug 10, 2007 1:21 am

I am using GLK12232-25-SM Rev1.4 board I2C interface. I found that the LCD module will tie SCL signal to low when in idle, but in I2C spec, it should be open and let the pull up resistor to pull it to high logic. I do not know why, is this an issue of Rev1.4 board? I checked the controller PIC16F877A datasheet, it can config the polarity of SCL in idle by CKP. Is it wrongly configed?
In my CPU board, I have a 4.7k pull up on SCL bus, so when connect the LCD module, this signal will be pull down to about 1.3v

Raquel · Post by **Raquel** » Fri Aug 10, 2007 11:08 am

Hello Shen,

With GLK12232-25-SM PCB 1.4, there are a couple extra steps necessary to put the display in I2C. Please check out this PCN

Best Regards,

shenli7 · Post by **shenli7** » Sun Aug 12, 2007 11:55 pm

Yeah, It works now, thx!