gfx example not working with ST7735 LCD.

[Jamie McCulloch]

I am trying to run the SDK15.3.0 gfx example code - only changing line 82 to:

 

static const nrf_lcd_t * p_lcd = &nrf_lcd_st7735;

 

And also I have changed the sdk_config to the display's width and height. I have wired it the same as in this https://devzone.nordicsemi.com/f/nordic-q-a/35606/st7735-interfacing-instructions which seems to match the config definitions.

I have tried the same display with an Arduino and it works fine there. However when I wire it up to the NRF52 DK the backlight turns on but no pixels change. The display I am using is and 160x80 LH096T ST7735 and the wiring I have done is as follows:

NRF52_DK	LCD
GND	GND
5V	VCC
P0.25	SCL
P0.23	SDA
P0.22	CS
P0.19	DC
VDD	RES
BLK	VDD

Any suggestions would be greatly appreciated.

[ovrebekk]

Hi Jamie

What is the expected voltage on the signalling pins?

Which Arduino board are you testing it with?

All the GPIO's on the nRF52DK are nominally around 3.0V, and if you supply the display with 5V (which your wiring table implies) you might have a voltage mismatch between the display and the nRF52DK. 

Can you try to supply the display from the 3V source and see if it works better?

Also, double check the specification of the display to make sure it will run at this voltage. 

Best regards
Torbjørn

[Jamie McCulloch]

Yes you are correct using 3V worked.

[ovrebekk]

Awesome