Hexadecimal to decimal

pnielsen · Mar 24, 2013

I am trying to convert hexidecimal to decimal in C code. If I uncommit the // the program will display ox141E into decimal. But I am stuped at the syntax to convert the hexadacimal to decimal. Any help would be tremendous.

Thank You

Philip

Code:

void Display_Result(void)
{
	
   // value 0x141E;
    LCD_Char_Position(0,6);
    LCD_Char_PrintInt8(HYT221_Read_Buff[0] & 0x3f);		//Mask HYT humidity the highest two status bits
	LCD_Char_PrintInt8(HYT221_Read_Buff[1]);
	LCD_Char_PrintString("      ");	
	LCD_Char_Position(1,6);
    sprintf(HYT221_Read_Buff, "0x%X", decimal_value);
  //   temp =(buffer, "%d", HYT221_Read_Buff[1]);        

  //   temp =(buffer, "%d", value);
  //   temp = (temp *100/16383);
  //   LCD_Char_Position(1,6);
  //  LCD_Char_PrintNumber(temp);
    
 }

/* [] END OF FILE */

jayanth.devarayanadurga · Mar 24, 2013

These two lines are incorrect.

// temp =(buffer, "%d", HYT221_Read_Buff[1]);
// temp =(buffer, "%d", value);

The RHS look like arguments to some function like printf but there are mistakes. I don't know how arguments to a function can be assigned to a variable. Post the full code so that it can be fixed.

betwixt · Mar 24, 2013

You can try the sscanf function. Use %X for the format field and give it the address of the variable to store the result.
Something like this: sscanf(HexNumber,"%X",&Result);.

The other method which may use less code is to convert each character to it's decimal value and add them together:
Result = (HexValue & 0xF000) * 4096;
Result += (HexValue & 0x0F00) * 256;
Result += (HexValue & 0x00F0) * 16;
Result += HexValue & 0x000F;

If you want to display using the code you already have, try changing the sprintf so it has %d in the format field instread of %X.

Brian.

doraemon · Mar 25, 2013

Hello!

I am trying to convert hexidecimal to decimal in C code.

You probably don't want to convert hexadecimal to decimal, but binary to text.
- Hexadecimal is just a representation to make binary readable by humans. If you write
a = 0x141E, a is not a hexadecimal value, it is just a 2-byte binary value. The most
significant byte is 20 and the least significant byte is 30. Hexadecimal does not exist as such
in your processor.
- A character LCD expects text.

Now if you want to display the decimal value of the variable (represented in hexa by 0x141E,
which is 5150), then you have to separate its 4 digits.

Code C - [expand]
1
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14
15
uint8 t, h, d, u; // For thousands, hundreds, tens (d for deca since t is used), u for units
uint16 val = 5150;
 
t = val / 1000; // You get t = 5
val -= 1000 * t; // You get 5150 - 5000 = 150;
h = val / 100; // You get h = 1
val -= 100*h; // You get val = 150 - 1*100 = 50
d = val/10; // You get d = 5;
u = val-10*d; // You get finally u = 0;
 
//Then, move to a place where there is enough space, and write the corresponding ascii values.
LCDWrite('0'+t);
LCDWrite('0'+h);
 
etc...

That should make it, right?

Note that this algorithm is inefficient because it uses divisions. I wrote another one on this
forum a few weeks ago, which is quite efficient because it replaces divisions by multiplications,
and which works for all values up to 2^14 if I remember correctly.

Dora.

pnielsen · Mar 25, 2013

betwixt said:
You can try the sscanf function. Use %X for the format field and give it the address of the variable to store the result.
Something like this: sscanf(HexNumber,"%X",&Result);.

The other method which may use less code is to convert each character to it's decimal value and add them together:
Result = (HexValue & 0xF000) * 4096;
Result += (HexValue & 0x0F00) * 256;
Result += (HexValue & 0x00F0) * 16;
Result += HexValue & 0x000F;

If you want to display using the code you already have, try changing the sprintf so it has %d in the format field instread of %X.

Brian.

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
Complete Code:

Code:

/*******************************************************************************
* File Name: main.c
*
* Version: 1.0
*
* Description:
*  
*
* Parameters used:
*  I2CM Master
*   Implementation        Fixed function
*   Data rate            100kbps
*   SDA SCL pin config  Open drain, drives low
*   Pull-up resistors    2.67k each
*
*
*
********************************************************************************
* Copyright 2012, Cypress Semiconductor Corporation. All rights reserved.
* This software is owned by Cypress Semiconductor Corporation and is protected
* by and subject to worldwide patent and copyright laws and treaties.
* Therefore, you may use this software only as provided in the license agreement
* accompanying the software package from which you obtained this software.
* CYPRESS AND ITS SUPPLIERS MAKE NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
* WITH REGARD TO THIS SOFTWARE, INCLUDING, BUT NOT LIMITED TO, NONINFRINGEMENT,
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*******************************************************************************/

#include <device.h>
#include <string.h>
/* HYT221 command define */
#define HYT_MR	0
#define HYT_DR	1
/* The I2CM Slave address by default in a PSoC device is 8 */
#define I2CM_SLAVE_ADDRESS    (0x28u)

/* The I2CM buffer define */
uint8 HYT221_Read_Buff[4] = {0};
uint8 HYT221_Write_Buff[4] = {0};

/* The HYT221 function define */
void HYT_MR_Initialization(void);
void HYT_DR_Operation(void);

/* The Display function define */
void  Display_Result(void);

/*******************************************************************************
* Function Name: main
********************************************************************************
*
* Summary:
*  main function performs following functions:
*
* Parameters:
*  None.
*
* Return:
*  None.
*
*******************************************************************************/
void main()
{
	/* Start I2CMm */
	I2CM_EnableInt();
    I2CM_Start();
    /* The LCD will display Standare info */
    LCD_Char_Start();
	LCD_Char_ClearDisplay();
	LCD_Char_Position(0,0);
    LCD_Char_PrintString("Hraw:");
	LCD_Char_Position(1,0);
    LCD_Char_PrintString("Traw:");

    /* Enable global interrupts - required for I2CM */
    CyGlobalIntEnable;

    for(;;)
    {
		HYT_MR_Initialization();
		HYT_DR_Operation();
		Display_Result();
        /* Delay introduced for ease of reading LCD */
        CyDelay(3000u/*ms*/);

    }  /* End forever loop */
} /* End main */

/*******************************************************************************
* Function Name: HYT_DR_Operation
********************************************************************************
*
* Summary:
*  Read HYT measurement result and put into HYT221_Read_Buff
*
* Parameters:
*  None.
*
* Return:
*  None.
*
*******************************************************************************/
void HYT_DR_Operation(void)
{
	uint8 status = 0;
	uint8 i;
	
	status = I2CM_MasterSendStart(I2CM_SLAVE_ADDRESS, HYT_DR);
	if(I2CM_MSTR_NO_ERROR == status) /* Check if transfer completed without errors */
	for(i=0; i<4; i++)
	{
		if(i < 3)
		{
			HYT221_Read_Buff[i] = I2CM_MasterReadByte(I2CM_ACK_DATA);
		}
		else
		{
			HYT221_Read_Buff[i] = I2CM_MasterReadByte(I2CM_NAK_DATA);
		}		
	}
	else
	{
		LCD_Char_Position(0,6);
	    LCD_Char_PrintString("Bus Error");
		LCD_Char_Position(1,6);
	    LCD_Char_PrintString("Bus Error");		
	}
	I2CM_MasterSendStop(); /* Send Stop */		
}

/*******************************************************************************
* Function Name: HYT_MR_Initialization
********************************************************************************
*
* Summary:
*  Initializate HYT enable a measure cycle
*
* Parameters:
*  None.
*
* Return:
*  None.
*
*******************************************************************************/
void HYT_MR_Initialization(void)
{
	uint8 status = 0;
	
	status = I2CM_MasterSendStart(I2CM_SLAVE_ADDRESS, HYT_MR);
	if(I2CM_MSTR_NO_ERROR == status) /* Check if transfer completed without errors */
	{
		//Delay to debug - If routine execute to here, only stop need to archive MR operation
		CyDelay(1);
	}
	else
	{
		LCD_Char_Position(0,6);
	    LCD_Char_PrintString("Bus Error");
		LCD_Char_Position(1,6);
	    LCD_Char_PrintString("Bus Error");		
	}
	I2CM_MasterSendStop(); /* Send Stop */		
}


/*******************************************************************************
* Function Name: Display_Result
********************************************************************************
*
* Summary:
*  Update LCD with latest result
*
* Parameters:
*  None.
*
* Return:
*  None.
*
*******************************************************************************/
void Display_Result(void)
{
	
   // value 0x141E;
    LCD_Char_Position(0,6);
    LCD_Char_PrintInt8(HYT221_Read_Buff[0] & 0x3f);		//Mask HYT humidity the highest two status bits
	LCD_Char_PrintInt8(HYT221_Read_Buff[1]);
	LCD_Char_PrintString("      ");	
	LCD_Char_Position(1,6);
//    sprintf(HYT221_Read_Buff, "0x%X", decimal_value);
  
//    sscanf((HYT221_Read_Buff,%x,&Result);
  //   temp = (temp *100/16383);
  //   LCD_Char_Position(1,6);
  //  LCD_Char_PrintNumber(temp);
    
 }

/* [] END OF FILE */

jayanth.devarayanadurga · Mar 25, 2013

What Compiler and MCU are you using?

betwixt · Mar 25, 2013

Now you have completely commented out the LCD routine so nothing will display.

In C, the sprintf, fprintf,and printf routines use a format field to control how the number is to be displayed. As draemon stated, a number is just a number, hex, binary, decimal and characters are just different ways of showing it. The format field controls which way the number is to be displayed or saved to a string or file. If you use "%d" it will display in decimal, %x will show the same number in hexadecimal , and %c will show it as equivalent characters and so on. If you want to control leading zeroes or decimal places, add the number (in decimal) of digits before and after a decimal point in the format field, for example %03.2f will show it with up to 3 leading zeroes and two decimal places.

Brian.

pnielsen · Mar 25, 2013

I am using Cypress MCU. It is a 8051. The actual part number is CY8C3866AXI-040, TQFP100. The compiler is made by Kiel. PK51 Professiona; Kit for PSOC

pnielsen · Apr 12, 2013

I have tried to use printf but I get error:
Verify Checksum...
Device 'PSoC 3 CY8C3866AX*-040' was successfully programmed at 04/12/2013 15:33:39.
Warning: Cannot set breakpoint: 'printf:read'. Encountered error (No symbol "printf" in current context.). _________________
Continuing target program
The target program has stopped at: file: line: -1 function: _PUTCHAR address: 0x00001C7F

#include <device.h>
#include <stdio.h>
#include <stdarg.h>

Any ideas? I think my compiler is very limited. It came with cypress free.

pnielsen · May 24, 2013

The issue is closed. If anyone is interested.

void Display_Result(void)
{
unsigned int result;

float buffer;
float final;
float Voltage;

union
{
unsigned int integer;
unsigned char byte[2];
}

temp16bitint;
temp16bitint.byte[0]=HYT221_Read_Buff[0] & 0x3f;
temp16bitint.byte[1]=HYT221_Read_Buff[1];
result = temp16bitint.integer;
LCD_Char_Position(1u,8u);
buffer=result;
final = ((buffer*100)/16383);
LCD_Char_PrintNumber(final);

Voltage=(final/1);

IDAC8_1_SetValue(Voltage);
// CyDelay(1500u/*ms*/);

Hexadecimal to decimal

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