Incompatible pointer assignment

[ankhola]

Hi Guys,

I am writing a code to measure a pulsating DC voltage. All that I have decided to take 50 samples and take the highest one.  Multiplying the peak value by a factor will give me the approximate RMS value. Please see my code. When built, an error “ Incompatible pointer assignment” shows. 

#include "stm8s.h"

unsigned int max_v;
unsigned k;
unsigned int val[100];

void Clock_Config(void) {
CLK->ICKR |= CLK_ICKR_HSIEN; // Enable HSI
while (!(CLK->ICKR & CLK_ICKR_HSIRDY)); // Wait for stabilization
CLK->CKDIVR = 0x00; // HSI 16MHz / 1 = 16MHz
CLK->SWR = 0xE1; // Use HSI as master clock
}

void adc_init(void)   {											
ADC1 -> CR1 =  0x40;
ADC1 -> CR2 = 0x08;
ADC1 -> TDRH = 0xFF;
ADC1 -> TDRL = 0xFF;
ADC1 -> CR1 |= ADC1_CR1_ADON;
			 }

uint16_t read_mains_value(void) {
unsigned int value;
ADC1 -> CSR = 0x05;
ADC1_StartConversion(); 
while(ADC1_GetFlagStatus(ADC1_FLAG_EOC) == FALSE);
value = ADC1_GetConversionValue(); 
ADC1_ClearFlag(ADC1_FLAG_EOC); // 
return value;    
}

void delay_us (int us) //Function Definition 
{
int i =0 ;
int j=0;
for (i=0; i<=us; i++)
{
for (j=0; j<16; j++) // Nop = Fosc/4
_asm("nop"); //Perform no operation //assembly code <span style="white-space:pre"> </span>
}
}


void main(void)
{

Clock_Config();

GPIO_Init(GPIOB, GPIO_PIN_5, GPIO_MODE_IN_FL_NO_IT);	
adc_init();	

for  ( k = 0; k<50; k++ ) {
val[k] =  read_mains_value;
delay_us(200);
                              }
max_v = 0;
  for ( k = 0; k < 50; k++) {
    if (val[k] > max_v) {
      max_v = val[k];
                        }
    val[k] = 0;
                                }

 

[Andrew Neil]

So where, exactly, does that error occur ?

 

This can’t be right:

val[k] =  read_mains_value;

Did you mean:

val[k] =  read_mains_value();

 

Also:

uint16_t read_mains_value(void) {
   unsigned int value;

You should make up your mind whether you’re using uint16_t or unsinged int

[ankhola]

Thanks Andrew Neil. I made a gross mistake. In place of  “read_mains_value()” I have written “read_mains_value”. Now the code has been built without error.

[Andrew Neil]

You’re welcome.

 

In C, when you give the name of a function without the parentheses, that gives the address of the function 0 ie, a pointer.

As the error message suggests, a pointer is not compatible with your var[k] for assignment.

 

 

 

[David Littell]

What, pray tell, is the shape of this “pulsating DC voltage”?  

[ankhola]

The shape is just positive half cycles of ac main. Actually, I want to measure the ac main voltage by  rectifying  the stepped down voltage. Precision is not so important.