ST7735 gfx demo ?

[RixtronixLAB]

Dear Members,

I saw ST7735_DC_PIN and ST7735_SS_PIN, which one should I connect to my LCD it has only CS pin ?

                                  ON LCD board
ST7735_SCK_PIN 47 --> P1.15       PIN 3     SCK

ST7735_MOSI_PIN 45 --> P1.13      PIN 4     MOSI SDA

ST7735_MISO_PIN 46 --> P1.14      PIN 6(RS) MISO

ST7735_SS_PIN 44 --> P1.12        PIN 7     CS

ST7735_DC_PIN 42 --> P1.10       PIN 7     CS

VDD                                 PIN 5 RES
                                         PIN 1 GND
                                         PIN 2 VCC
VDD                                 PIN 8 LEDA

Thanks

[Øyvind]

Hello, 

I'm not sure this is the correct forum to ask. Have you read the manual of the display?

Kind regards,
Øyvind

[RixtronixLAB]

How to wire this LCD ?

Where can I connect RES, RS ?

It has ST7735 chipset but I'm not sure on how to wire it with sdk_config.h

// <o> ST7735_SCK_PIN - Pin number  <0-47>


#ifndef ST7735_SCK_PIN
#define ST7735_SCK_PIN 47
#endif

// <o> ST7735_MISO_PIN - Pin number  <0-47>


#ifndef ST7735_MISO_PIN
#define ST7735_MISO_PIN 46
#endif

// <o> ST7735_MOSI_PIN - Pin number  <0-47>


#ifndef ST7735_MOSI_PIN
#define ST7735_MOSI_PIN 45
#endif

// <o> ST7735_SS_PIN - Pin number  <0-47>


#ifndef ST7735_SS_PIN
#define ST7735_SS_PIN 44
#endif

// <o> ST7735_DC_PIN - Pin number  <0-47>


#ifndef ST7735_DC_PIN
#define ST7735_DC_PIN 42
#endif

[Øyvind]

Hello, 

What version of the nRF5 SDK are you using? You need to look in the datasheet of the display to find the function of each pin.

If this is a SPI device, remember that SS (Slave Select) = CS (Chip Select). I don't know what RS, RES or DC do. Searching DevZone, I found the following thread which might be of interest: https://devzone.nordicsemi.com/f/nordic-q-a/53165/gfx-example-not-working-with-st7735-lcd. 

From examples\peripheral\gfx\pca10040\blank\config\sdk_config.h (nRF5 SDK v16.0.0) I found the following config settings:

// <e> ST7735_ENABLED - st7735 - ST7735R TFT controller
//==========================================================
#ifndef ST7735_ENABLED
#define ST7735_ENABLED 1
#endif
// <h> SPI_CONFIGURATION - SPI configuration

// <o> ST7735_SCK_PIN - Pin number  <0-47> 


#ifndef ST7735_SCK_PIN
#define ST7735_SCK_PIN 25
#endif

// <o> ST7735_MISO_PIN - Pin number  <0-47> 


#ifndef ST7735_MISO_PIN
#define ST7735_MISO_PIN 24
#endif

// <o> ST7735_MOSI_PIN - Pin number  <0-47> 


#ifndef ST7735_MOSI_PIN
#define ST7735_MOSI_PIN 23
#endif

// <o> ST7735_SS_PIN - Pin number  <0-47> 


#ifndef ST7735_SS_PIN
#define ST7735_SS_PIN 22
#endif

// <o> ST7735_IRQ_PRIORITY  - Interrupt priority
 

// <i> Priorities 0,2 (nRF51) and 0,1,4,5 (nRF52) are reserved for SoftDevice
// <0=> 0 (highest) 
// <1=> 1 
// <2=> 2 
// <3=> 3 
// <4=> 4 
// <5=> 5 
// <6=> 6 
// <7=> 7 

#ifndef ST7735_IRQ_PRIORITY
#define ST7735_IRQ_PRIORITY 6
#endif

// </h> 
//==========================================================

// <o> ST7735_SPI_INSTANCE
 
// <0=> 0 
// <1=> 1 
// <2=> 2 

#ifndef ST7735_SPI_INSTANCE
#define ST7735_SPI_INSTANCE 0
#endif

// <o> ST7735_TAB_COLOR  - Color of the tab attached to the screen.
 
// <0=> INITR_GREENTAB 
// <1=> INITR_REDTAB 
// <2=> INITR_BLACKTAB 
// <3=> INITR_144GREENTAB 

#ifndef ST7735_TAB_COLOR
#define ST7735_TAB_COLOR 0
#endif

// <o> ST7735_DC_PIN - Pin number  <0-47> 


#ifndef ST7735_DC_PIN
#define ST7735_DC_PIN 19
#endif

// <o> ST7735_HEIGHT - ST7735 height  <0-162> 


#ifndef ST7735_HEIGHT
#define ST7735_HEIGHT 160
#endif

// <o> ST7735_WIDTH - ST7735 width  <0-132> 


#ifndef ST7735_WIDTH
#define ST7735_WIDTH 128
#endif

// </e>

// </h> 
//==========================================================

I also recommend looking at the drivers of the ST7735:
components\drivers_ext\st7735\st7735.c

The API reference in our Infocenter: https://infocenter.nordicsemi.com/topic/sdk_nrf5_v16.0.0/group__st7735__config.html

When you have connected correctly, have a loot at the GFX Library sample.

Kind regards,
Øyvind