e-paper display with spi. (hardware pins - digital write -baud-rate)

[AMG]

Hello,

Sorry if it will be long. thanks for the help.

Using nrf9160 dk. The first thing I want to ask is about is the pins. I want to make sure I am using the correct pin. I think most of the pins can be used for digital I/O so that leave the sck,MISO.MOSI. 

#define sck_pin   13     //p.13
#define sda_pin   12     //p.12   MISO
#define cs_pin    11     //p.11   MOSI
#define dc_pin    21     //       digital pin pwd   
#define reset_pin 22     //       digital pin pwd
#define busy_pin  23     //       digital pin pwd
#define pnlon_pin 24     //       digital pin pwd
#define bs_pin    25     //       digital pin pwd
#define css_pin   26     //       digital pin pwd

The second thing is that I am trying to digital write to pin high/low. similar to the Arduino digital write(). So I looked and found  nrf_gpio_pin_write ( uint32_t pin_number, uint32_t value ) OR  should use gpio_pin_write(struct device *port, gpio_pin_t pin, u32_t value)

Also to set-up a pin to output/input  GPIO_INPUT /  GPIO_OUTPUT can be used right.

Last question to begin the serial link I couldn't find anything about that except for spi_cfg.frequency = 115200;  but that doesn't work.

I looked also into the blinky example and devicetree still confused.

[AMG]

Hi Simon, 

I configured the files according to your input.Since I cant upload a zip file I created a link to the drive. Now when I try to flash the code the nrf9160 dk just go in to a loop or a core dump. I have printk in the start and end of the main function but nothing is printed.

Update:

struct device *dev;
dev = device_get_binding("SPI_3");     

The SPI_3 causes core dump. what Pointer to the device structure for the driver instance should I use.

Kind regards

[Simon]

Why are you using the GPIO peripheral to communicate with the display? You should instead use the SPI peripheral.

Instead of using the function gpio_pin_set(), use the function spi_transceive().

The reason the below code crashes is because you're getting the binding to an spi instance, and using functions (gpio_pin_set()) intended for a GPIO binding.

struct device *dev;
dev = device_get_binding("spi3");

  for ( int i = 0; i < 8; i++ ) {
    if ((( data >> (7 - i) ) & 0x01 ) == 1 ) 
    gpio_pin_set(dev,miso_pin, 1 );
    else gpio_pin_set(dev, miso_pin, 0 );
    gpio_pin_set(dev,sck_pin, 1 );
    gpio_pin_set(dev,sck_pin, 0 );
  }

I would recommend you to look at some SPI samples to see how to use the SPI functions. E.g. sdk-zephyr/main.c at 3366927a54986ad0ddf060d0e08ecc578adf11f0 · nrfconnect/sdk-zephyr · GitHub

What kind of display are you using? It may be some already working examples/drivers that you can use: sdk-zephyr/samples/display at 3366927a54986ad0ddf060d0e08ecc578adf11f0 · nrfconnect/sdk-zephyr · GitHub, where you use a higher abstraction layer than the SPI functions.

Best regards,

Simon

[AMG]

The display I am using is pervasive display 12 inch, looked into the available display examples nothing is really relevant and quite limited. Since I am setting the pins output so went with GPIO, digitally write to the pin so, went with the function you recommended (gpio_pin_set).will have a look into the SPI functions.

[Simon]

Initially I thought that you were going to use gpio_pin_set() for something else, sorry for confusing you. Please ask more question if you don't get it to work using the SPI functions. If you're new to NCS it can be a bit overwhelming, but as soon as you've learned about the different abstraction layers, Kconfigs and the device tree it's much easier to work with.

Best regards,

Simon

[AMG]

Thanks, I am slowly getting the hang of it. Couple more question. The following code is the one runs on the arduino MKR1500 I created for the Pervasive display it works without any problems. It doesn't use any spi funcations. I tried to follow that with the nRF.  The code as you can see I am using gpio functions. 



That's why I tried to use the gpio_configure , gpio_set , gpio_ get funcations. 

If I start using the spi functions how is it going to look like. what other function I might use for the read and configuration of the pins (output,input) or should I stick with using the gpio.

Other issue the printk is not printing does that mean the code is running??