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Topics - ericdeyoung19

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Character LCDs / NHD-C0216CZ-FSW-FBW-3V3
« on: January 11, 2016, 08:27:43 AM »
I am having trouble getting this screen to acknowledge my I2C commands.  I have tried two PCBs with different screens and verified signals, but I still can't get the LCD to acknowledge a command - not even the I2C address (which should be 0x7C according to the datasheet).  The additional data below is only while trying to get an acknowledgement from the screen when writing the address to the device.  My current code is as follows:

LCD_RESET_LOW;
_delay_ms(2);
LCD_RESET_HIGH;
_delay_ms(20);
   
LCD_SELECT_INSTRUCTION;
TWI_start();
LCD_write(LCD_ADDRESS);
TWI_stop();

_delay_ms(10);


I have verified that pin 7 is at 3.3V, RST is fixed at a high level, RS is fixed at a low level, and you can see the CS line, SCL line, and SDA line in the oscilloscope shot.  Just to be sure that the pinout is correct, when looking at the back of the screen, pin 1 is on the left side.

When powered up, should the C+ and C- pins be switching at all by default?  What level should VOUT be after a reset condition?

Thanks!


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