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Topics - SteveC

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1
Hello,

I have a question about the sample code for the  NHD‐C0220BiZ‐FS(RGB)‐FBW‐3VM LCD which follows this text.

My question is why the Function Set with 0x38 and then 0x39?

Also it would be most helpful to have comments on each line of the sample code to better understand how the ST7036 controller actually works.

Thanks for any help with my understanding.

Best Regards,

SteveC

/****************************************************
*           Initialization For ST7036i              *
*****************************************************/
void init_LCD()
{
I2C_Start();
I2C_out(Slave);
I2C_out(Comsend);
I2C_out(0x38);
delay(10);
I2C_out(0x39);
delay(10);
I2C_out(0x14);
I2C_out(0x78);
I2C_out(0x5E);
I2C_out(0x6D);
I2C_out(0x0C);
I2C_out(0x01);
I2C_out(0x06);
delay(10);
I2C_Stop();
}

2
Hello,

I've built 3 prototypes using the NHD‐C0220BiZ‐FS(RGB)‐FBW‐3VM LCDs and all 3 stay blank all the time. Here are the voltages on the pins... all 3 read almost identically:
Pin #1 - /RESET - 3.30V
Pin #2 - SCL - 3.63V
Pin #3 - SDA - 3.63V
Pin #4 - Vss - 0.00V
Pin #5 - VDD - 3.30V
Pin #6 - VOUT - 2.97V
Pin #7 - C+ - 3.28V
Pin #8 - C- - 0.02V

I'm a bit concerned with Pin#6 as it seems the voltage converter isn't working. I'm using 1uF, 25V MLCCs across pin #7 and #8. Plus another from pin #6 to pin #4. Reset is pulled up to 3.3V with a 10K resistor. The microcontroller has weak pullups to +5V which is why SCL and SDA are a bit higher than 3.3V.

I've tried using the evaluation software and 2 different microcontroller eval boards but nothing seems to help. The LCDs are always completely blank.

I've tried changing the Slave Address to 0x7C but no change.

I should also add that I've looked at the I2C signals on a scope and they look OK. SCL is running at 100KHz and the software example just keeps running in the loop.

Any help would be most appreciated. I must be missing something very basic.... arggg.....

Is there any possibility the pinouts for Vdd and Vss are switched? Perhaps Pin #4 is Vdd (+3.3V) and Pin #5 is Vss (0.0v)? Or should this display run at Vdd = 5V?

Thank you.

Pages: [1]