Can't use uGFX with ST7735 on nrf51

[IlyaM]

Hey, I gonna use uGFX with ST7735, unfortunately there is no board_ST7735_template.h for this driver and I wrote my own:

#ifndef GDISP_LLD_BOARD_H
#define GDISP_LLD_BOARD_H

#include "nrf_gpio.h"
#include "nrf_drv_spi.h"
#include "nrf_delay.h"
#include "nrf_log.h"
#include "app_error.h"

#define GDISP_LLD_PIXELFORMAT			GDISP_PIXELFORMAT_RGB565

#define LCD_SCK     29
#define LCD_MISO    22
#define LCD_MOSI    28
#define LCD_CS      24
#define LCD_DC      20
#define LCD_RST     23
//#define LCD_RW      6

#define SPI_INSTANCE  1 /**< SPI instance index. */
static const nrf_drv_spi_t spi = NRF_DRV_SPI_INSTANCE(SPI_INSTANCE);  /**< SPI instance. */
nrf_drv_spi_config_t lcd_spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
static volatile bool lcd_spi_xfer_done;  /**< Flag used to indicate that SPI instance completed the transfer. */

void lcd_spi_event_handler(nrf_drv_spi_evt_t const * p_event)
{
    lcd_spi_xfer_done = true;
    //NRF_LOG_DEBUG("spi transfer completed.\n");
}

static GFXINLINE void init_board(GDisplay *g) {
  NRF_LOG_RAW_INFO("ST7735 init_board\n");
  // setup pins
  nrf_gpio_cfg_output(LCD_CS);
  nrf_gpio_cfg_output(LCD_DC);
  nrf_gpio_cfg_output(LCD_RST);
  //nrf_gpio_cfg_output(LCD_RW);

  nrf_gpio_pin_write(LCD_CS, 1);
  //nrf_gpio_pin_write(LCD_RW, 1);

  // reset board
  nrf_gpio_pin_write(LCD_RST, 0);
  nrf_delay_ms(100);
  nrf_gpio_pin_write(LCD_RST, 1);

  // setup spi
  lcd_spi_config.miso_pin = LCD_MISO;
  lcd_spi_config.mosi_pin = LCD_MOSI;
  lcd_spi_config.sck_pin  = LCD_SCK;
  lcd_spi_config.frequency = NRF_DRV_SPI_FREQ_8M;
  APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &lcd_spi_config, lcd_spi_event_handler));
	(void) g;
}

static GFXINLINE void post_init_board(GDisplay *g) {
	(void) g;
}

static GFXINLINE void setpin_reset(GDisplay *g, gBool state) {
  NRF_LOG_RAW_INFO("setpin_reset: %d\r\n", state);
  nrf_gpio_pin_write(LCD_RST, state);
	(void) g;
	(void) state;
}

static GFXINLINE void set_backlight(GDisplay *g, uint8_t percent) {
	(void) g;
	(void) percent;
}

static GFXINLINE void acquire_bus(GDisplay *g) {
  nrf_gpio_pin_write(LCD_CS, 0);
	(void) g;
}

static GFXINLINE void release_bus(GDisplay *g) {
  nrf_gpio_pin_write(LCD_CS, 1);
	(void) g;
}

static GFXINLINE void write_cmd(GDisplay *g, uint8_t cmd) {
  // dc low
  nrf_gpio_pin_write(LCD_DC, 0);
  lcd_spi_xfer_done = false;
  APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, &cmd, 1, NULL, 0));
  //while (!lcd_spi_xfer_done){};
	(void) g;
	(void) cmd;
}

static GFXINLINE void write_data(GDisplay *g, uint8_t data) {
	(void) g;
	(void) data;
  nrf_gpio_pin_write(LCD_DC, 1);
  lcd_spi_xfer_done = false;
  APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, &data, sizeof(data), NULL, 0));
  //while (!lcd_spi_xfer_done){};
}

static GFXINLINE void write_data_byte(GDisplay *g, uint8_t arg) {
  // dc high
  nrf_gpio_pin_write(LCD_DC, 1);
  lcd_spi_xfer_done = false;
  APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, &arg, 1, NULL, 0));
  //while (!lcd_spi_xfer_done){};
	(void) g;
	(void) arg;
}

static GFXINLINE uint16_t read_data(GDisplay *g) {
	(void) g;
	return 0;
}

#endif /* GDISP_LLD_BOARD_H */

nrf51 doesn't have systick and instead of this one I use RTC timer with frequency 32kHz, but when I compile it (without errors) I see nothing on my display and in the console output. if I comment out everything with uGFX I see console output, more over I have my own lib for ST7735 and it works fine. May I use uGFX without systick, I think it needs for display's backligh?

Maybe someone had have an experience with this display and nrf51822?

[Joel Bodenmann]

Please excuse the late reply - I wanted to digg out some sources.

We've plenty of people that use µGFX on nRF51 and nRF52 platforms. The nRF51 does have a systick. I've attached a GOS port and the corresponding systick handler implementation for an nRF51 port I made quite some time ago.  

In general: You might want to check whether the µGFX core runs before starting to use optional modules such as GDISP and GINPUT. You can have a look at the GOS demos - they allow you to check whether the µGFX core is working correctly without using the display code.

ugfx_port.c

gos_nrf5sdk11.c

gos_nrf5sdk11.h