problem with ili9341 touch interface using stm32f103ret6

[salar1991]

Hi, I successfully used a HAL library to drive a TFT ili9341 LCD and tried drawing a line on the LCD by touching the LCD and the code was perfectly accurate then I rewrote the code with registers. the touch is not accurate now and when I touch the LCD the line shows up at a point far from the place which is touched I attached the code. what might be the problem? the pins are defined with maximum frequency.

#include "ILI9341_Touchscreen.h"
#include "stm32f10x.h"
#include "main.h"
 
//Internal Touchpad command, do not call directly
uint16_t TP_Read(void)
{
    uint8_t i = 16;
    uint16_t value = 0;
 
    while(i > 0x00)
    {
        value <<= 1;
 
				
			   TP_CLK_PORT->BSRR=TP_CLK_PIN;
			   TP_CLK_PORT->BRR=TP_CLK_PIN;
			
        
					if ((TP_MISO_PORT->IDR&TP_MISO_PIN)!=0)
        {
            value++;
        }
 
        i--;
    };
 
    return value;
}
 
//Internal Touchpad command, do not call directly
void TP_Write(uint8_t value)
{
    uint8_t i = 0x08;
 
		TP_CLK_PORT->BRR=TP_CLK_PIN;
	
    while(i > 0)
    {
        if((value & 0x80) != 0x00)
        {
						
					TP_MOSI_PORT->BSRR=TP_MOSI_PIN;
        }
        else
        {
						TP_MOSI_PORT->BRR=TP_MOSI_PIN;
        }
 
        value <<= 1;
				TP_CLK_PORT->BSRR=TP_CLK_PIN;
				TP_CLK_PORT->BRR=TP_CLK_PIN;        
        i--;
    };
}
 
 
 
//Read coordinates of touchscreen press. Position[0] = X, Position[1] = Y
uint8_t TP_Read_Coordinates(uint16_t Coordinates[2])
{
		TP_CLK_PORT->BSRR=TP_CLK_PIN;		
		TP_MOSI_PORT->BSRR=TP_MOSI_PIN;			
	  TP_CS_PORT->BSRR=TP_CS_PIN;
 
	
	
    uint32_t avg_x, avg_y = 0;		
		uint16_t rawx, rawy = 0;	
		uint32_t calculating_x, calculating_y = 0;
	
    uint32_t samples = NO_OF_POSITION_SAMPLES;
    uint32_t counted_samples = 0;
 
		
	TP_CS_PORT->BRR=TP_CS_PIN;
 
	
    while((samples > 0)&&((TP_IRQ_PORT->IDR)& TP_IRQ_PIN) == 0)
    {			
        TP_Write(CMD_RDY);
 
				rawy = TP_Read();	
				avg_y += rawy;
				calculating_y += rawy;
 
				
        TP_Write(CMD_RDX);
        rawx = TP_Read();
				avg_x += rawx;
				calculating_x += rawx;
        samples--;
				counted_samples++;
    };
		
		TP_CS_PORT->BSRR=TP_CS_PIN;
 
		
		if((counted_samples == NO_OF_POSITION_SAMPLES)&&((TP_IRQ_PORT->IDR)&TP_IRQ_PIN) == 0)
		{
		
		calculating_x /= counted_samples;
		calculating_y /= counted_samples;
		
		rawx = calculating_x;
		rawy = calculating_y;		
		
		rawx *= -1;
		rawy *= -1;
		
		//CONVERTING 16bit Value to Screen coordinates
    // 65535/273 = 240!
		// 65535/204 = 320!
    Coordinates[0] = ((240 - (rawx/X_TRANSLATION)) - X_OFFSET)*X_MAGNITUDE;
		Coordinates[1] = ((rawy/Y_TRANSLATION)- Y_OFFSET)*Y_MAGNITUDE;
		
		return TOUCHPAD_DATA_OK;			
		}
		else
		{
			Coordinates[0] = 0;
			Coordinates[1] = 0;
			return TOUCHPAD_DATA_NOISY;
		}
}
 
//Check if Touchpad was pressed. Returns TOUCHPAD_PRESSED (1) or TOUCHPAD_NOT_PRESSED (0)
uint8_t TP_Touchpad_Pressed(void)
{
	if((TP_IRQ_PORT->IDR&TP_IRQ_PIN) == 0)
	{
		return TOUCHPAD_PRESSED;
	}
	else
	{
		return TOUCHPAD_NOT_PRESSED;
	}
}
 
 

[MM..1]

Why this ugly code ??? Try show how HAL you mean

When you comunicate with chip that uses SPI , you need too use SPI , any gpio simulating is trouble

For example how is clock speed and duty when you start write ??

...
				TP_CLK_PORT->BSRR=TP_CLK_PIN;
				TP_CLK_PORT->BRR=TP_CLK_PIN;        

[salar1991]

I'm sorry I didn't mention that it is only part of the code that is related to touch I didn't bring the part about SPI because that part works fine. I used SPI to communicate with the ili9341 and I am able to draw pixels with the desired color. but for the touch IC, I am using GPIO like this example https://github.com/martnak/STM32-ILI9341

i used macros to rename the pins and the GPIO configuration is in another library which is called by a function in the main I can include it here if you like

#include "stm32f10x.h"
 
void GPIO_init(void){
	
RCC->APB2ENR |=(1<<4);
RCC->APB2ENR |=(1<<2);	
GPIOC->CRL &=~0xF00FFFFF; //// Clearing C0 to C4
GPIOC->CRL |= 0x30033834;  //// configuring C0 input floating , C1 , C3, C4 output pushpull C2 input with pull up/pull down 
GPIOC->ODR |=(1<<2); ///	making C2 pull up
GPIOC->CRH &=~0xF0000F; /// clearing C13 and C8
GPIOC->CRH |= 0x300003;	// C13 and C8 output push pull
 
}

#ifndef __MAIN_H
#define __MAIN_H
 
#ifdef __cplusplus
extern "C" {
#endif
 
 
#include "stm32f10x.h"
 
 
 
void Error_Handler(void);
 
 
 
/* Private defines -----------------------------------------------------------*/
#define DC_Pin (1<<13)
#define DC_GPIO_Port GPIOC
#define T_IRQ_Pin (1<<0)
#define T_IRQ_GPIO_Port GPIOC
#define T_CLK_Pin (1<<1)
#define T_CLK_GPIO_Port GPIOC
#define T_MISO_Pin (1<<2)
#define T_MISO_GPIO_Port GPIOC
#define T_MOSI_Pin (1<<3)
#define T_MOSI_GPIO_Port GPIOC
#define T_CS_Pin (1<<4)
#define T_CS_GPIO_Port GPIOC
#define CS_Pin (1<<7)
#define CS_GPIO_Port GPIOC
#define RST_Pin (1<<8)
#define RST_GPIO_Port GPIOC
 
 
#ifdef __cplusplus
}
#endif
 
#endif 
 
 

[salar1991 · Accepted solution]

I defined a dummy variable a and wrote a++ between

TP_CLK_PORT->BRR=TP_CLK_PIN;

 and 

if ((TP_MISO_PORT->IDR&TP_MISO_PIN)!=0)

It works fine now! my problem is solved. I think the reason it didn't work well was that I was violating the 200ns tCH spec based on the datasheet. the reason that the HAL code worked might be because the HAL code instructions take a longer time to operate.