SAM3X SPI troubleshooting

Development Boards MicroMod
1

I am using a custom board SAM3X8C and am having some trouble programming (Atmel Studio 6) the SPI interface to work with my ILI9341 LCD. The LCD module works with a separate board using an atmega2560 so I don’t believe the fault to be with the LCD itself. When I run the code provided below all I see is a blank screen (the backlight is on whenever there is power). All I am trying to accomplish is the fill the screen an arbitrary color (I can hopefully figure out the rest from there).

I am trying to use the ASF library for the “LCD - ILI9341 Display Controller (component)”. Following the example provided by Atmel’s ASF documentation (http://asf.atmel.com/docs/latest/sam3x/ … group.html and http://asf.atmel.com/docs/latest/sam3x/ … 41_qs.html) I have configured the conf_ili9341 header file as such:

#define CONF_ILI9341_CLOCK_SPEED		8000000UL
#define CONF_ILI9341_SPI			SPI0
#define CONF_ILI9341_CS_PIN			PIO_PA28_IDX
#define CONF_ILI9341_DC_PIN			PIO_PB3_IDX
#define CONF_ILI9341_BACKLIGHT_PIN	PIO_PA21_IDX
#define CONF_ILI9341_RESET_PIN		PIO_PA29_IDX

The hardware side has been checked and re-checked over and over and looks correct. Following the datasheet I have SPI0 configured to use peripheral A and the pinout is reflected in the initialization inside main().

#include "asf.h"
#include "conf_board.h"
#include "conf_clock.h"
#include "conf_ili9341.h"

int main(void)
{
	sysclk_init();
	board_init();
	
	pio_set_peripheral(PIOA, PIO_PERIPH_A, PIO_PA25A_SPI0_MISO);
	pio_set_peripheral(PIOA, PIO_PERIPH_A, PIO_PA26A_SPI0_MOSI);
	pio_set_peripheral(PIOA, PIO_PERIPH_A, PIO_PA27A_SPI0_SPCK);
	pio_set_peripheral(PIOA, PIO_PERIPH_A, PIO_PA28A_SPI0_NPCS0);
	
	pmc_enable_periph_clk(ID_SPI0);
	
	ili9341_init();
	ili9341_backlight_on();
	ili9341_set_top_left_limit(0, 0);
	ili9341_set_bottom_right_limit(240, 320);
	ili9341_duplicate_pixel(ILI9341_COLOR(200, 20, 130), 240UL * 320UL);
}

Can anyone offer any suggestions on where to troubleshoot next or different code to try? Maybe I am just missing part of the SPI or LCD initialization. I am at a loss right now. I don’t have a scope to monitor the SPI lines unfortunately. I know the ASF wizard can be a bit funky to use correctly, so if anyone thinks that is the problem, could you suggest the right way to do it? Any and all feedback will be greatly appreciated!

2

The following code workflow solved my issue.

sysclk_init();
	board_init();
	
	pmc_enable_periph_clk(ID_PIOA);
	pmc_enable_periph_clk(ID_PIOB);
	
	pio_set_output(PIOA, PIO_PA29, LOW, DISABLE, ENABLE);	// reset
	pio_set_output(PIOB, PIO_PB3, LOW, DISABLE, ENABLE);	// dcx
	
	pio_set_peripheral(PIOA, PIO_PERIPH_A, PIO_PA25A_SPI0_MISO);
	pio_set_peripheral(PIOA, PIO_PERIPH_A, PIO_PA26A_SPI0_MOSI);
	pio_set_peripheral(PIOA, PIO_PERIPH_A, PIO_PA27A_SPI0_SPCK);
	pio_set_peripheral(PIOA, PIO_PERIPH_A, PIO_PA28A_SPI0_NPCS0);
	
	pmc_enable_periph_clk(ID_SPI0);
	
	spi_enable(SPI0);
	spi_master_init(SPI0);
	
	ili9341_init();
	ili9341_backlight_on();
	ili9341_set_top_left_limit(0, 0);
	ili9341_set_bottom_right_limit(320, 240);
   ili9341_duplicate_pixel(ILI9341_COLOR(200, 20, 130), 240UL * 320UL);

Thanks anyways! Hopefully this will help someone like me in the future. It could probably be simplified a lot anyways.