Update char array with Int and float values, without sprintf? - c

Question

I am using C to program a microcontroller (NHS3152) to calculate resistance using this formula:
RES = (V1-V2)/I
I want to write a program that:
Updates the values of 3 Floats and 1 integer (V1, V2, I, RES)
Update uint8_t text[] = "Char to store values of V_1, V_2, I, Res"; with a string with the values of these 3 floats and 1 integer
Commits text to memory using the function: "Example1_Creating_an_NDEF..." (provided below)
The issue I am having is with Updating text with the values of the 3 floats and 1 integer. I am able to do it with sprintf, however I cannot use this function with my microcontroller (I dont know why it stops me from flashing it to memory)
The code bellow is an example of what i want to achieve in from point 2 above, in the real code the float and integer values are updated by getting values from sensors on the mircocontroller:
#include <stdio.h>
#include <stdint.h>
static volatile float V_1 = 5.0; // store value of Voltage 1
static volatile float V_2 = 2.0; // store value of voltage 2
static volatile int I = 5; // store current value
static volatile float RES; // calcualte resitance
int i=1;
uint8_t text[] = "Char to store values of V_1, V_2, I, Res";
int main(void)
{
printf( text);
printf("\n");
//updates values for ADC_1, ADC_2, I, Res,
while(i<=2){ // real while loop is infinite
V_1 ++ ; // Usually value updates from microcontroller sensor
V_2 ++ ;
I ++;
RES = (V_1-V_2)/I; // calculating resistance
sprintf((char *)text, "Updated Text V1: %6.2f V2: %6.2f I: %8.d resistance: %e", V_1, V_2,I, RES ); // what i want to do but without sprintf
printf( text);
printf("\n");
i++;
}
printf("END");
}
OUT:
Char to store values of V_1, V_2, I, Res
Updated Text V1: 6.00 V2: 3.00 I: 6 resistance: 5.000000e-01
Updated Text V1: 7.00 V2: 4.00 I: 7 resistance: 4.285714e-01
END
Here is the Code including the function Example1_Creating_an_NDEF.. from point 3. This working code manages to Commit the text to memory (it works). All i need is to be able to update the text without sprintf as i believe these functions aren't allowed when i'm not in debug mode.
#include "board.h"
// From ndeft2t
#include "ndeft2t/ndeft2t.h"
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
uint8_t instance[NDEFT2T_INSTANCE_SIZE] __attribute__((aligned (4)));
uint8_t buffer[NFC_SHARED_MEM_BYTE_SIZE ] __attribute__((aligned (4)));
uint8_t locale[] = "en";
uint8_t text[] = "Char to store values of V_1, V_2, I, Res";
// I want to add these to the text message
static volatile float V_1 = 5.0;
static volatile float V_2 = 2.0;
static volatile int I = 5;
static volatile float Res = ;
static void Example1_Creating_an_NDEF_Message_with_a_single_record_of_type_TEXT (void)
{
Chip_NFC_Init(NSS_NFC); /* Is normally already called during board initialization. */
NDEFT2T_Init();
NDEFT2T_CreateMessage(instance, buffer, NFC_SHARED_MEM_BYTE_SIZE, true);
NDEFT2T_CREATE_RECORD_INFO_T recordInfo = {.shortRecord = true, .pString = locale};
if (NDEFT2T_CreateTextRecord(instance, &recordInfo)) {
/* The payload length to pass excludes the NUL terminator. */
if (NDEFT2T_WriteRecordPayload(instance, text, sizeof(text) - 1)) {
NDEFT2T_CommitRecord(instance);
}
}
NDEFT2T_CommitMessage(instance);
/* The return value of the commit function is ignored here. */
}
int main(void)
{
Board_Init();
//NDEFT2T_Init();
/* Optional feature: send the ARM clock to PIO0_1 */
Chip_IOCON_SetPinConfig(NSS_IOCON, IOCON_PIO0_1, IOCON_FUNC_1);
Chip_Clock_Clkout_SetClockSource(CLOCK_CLKOUTSOURCE_SYSTEM);
/* Blink & attach a message to Memory */
while (1) {
//updates values for V_1, V_2, I, Res,
V_1++;
V_2++;
I++;
RES = (V_1 - V_2)/RES;
// Update the text message to contain "(V_1, V_2, I, RES)"
LED_Toggle(LED_RED);
Example1_Creating_an_NDEF_Message_with_a_single_record_of_type_TEXT();
Chip_Clock_System_BusyWait_ms(500);
}
return 0;
}
EDIT: responding to KamilCuk's comment : Do you really need float? Does your mcu has floating point support? Consider using integers only.
The fucntions i use to get V1,V2 & I, all return an Integer (eg: V1=2931 12 bit converter so between 0 and 4096 ) however to convert the integer value to the real value i need to use the following conversion:
V1_real= (V1* 1.2) / 2825 + 0.09; // CONVERSION added line
Without conversion i Cannot calculate Res.
An acceptable compromise is to commit to memory the values V1, V2, I without converstion to real values. I can then calculate RES in a second momemnt, once i retrieve the data from the MCU ( i am using my phone as an NFC reader, the chip is an NFC tag)
So the question is:
How do i convert the message in text to a message containing the integers (V_1,V_2,I)? :
Something like:
uint8_t text[] = "Char to store values of V_1, V_2, I";
text = "Message with V_1: V_1value, V_2: V_2value, I: IValue
Below is the code i use to extract the value of V_1 & V_2:
void adc (void)
{
Chip_IOCON_SetPinConfig(NSS_IOCON, IOCON_ANA0_1, IOCON_FUNC_1);
Chip_ADCDAC_SetMuxADC(NSS_ADCDAC0, ADCDAC_IO_ANA0_1);
Chip_ADCDAC_SetInputRangeADC(NSS_ADCDAC0, ADCDAC_INPUTRANGE_WIDE);
Chip_ADCDAC_SetModeADC(NSS_ADCDAC0, ADCDAC_SINGLE_SHOT);
Chip_ADCDAC_StartADC(NSS_ADCDAC0);
//Getting the data
while (!(Chip_ADCDAC_ReadStatus(NSS_ADCDAC0) & ADCDAC_STATUS_ADC_DONE)) {
; /* Wait until measurement completes. For single-shot mode only! */
}
//Data V1 stored here
adcInput_1 = Chip_ADCDAC_GetValueADC(NSS_ADCDAC0);
// Usually i use this line to then conver it to the real value of V1
//adcInput_1= (adcInput_1 * 1.2) / 2825 + 0.09; // CONVERSION added line
//! [adcdac_nss_example_3]
}
Maybe someone has a better solution that allows me to actually arrive at having also RES calculated, knowing that:
RES= V1_real-V1_real/I_real
V1_real= (V1* 1.2) / 2825 + 0.09 and 0< V1 < 4000 (12 bit converter for V1)
V2_real= (V2* 1.2) / 2825 + 0.09 and 0< V2 < 4000
I_real = I*1e-12 0<I<4000