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Error: Previous identifier must be a pointer

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pyu

Joined: 04 Feb 2009
Posts: 51

Error: Previous identifier must be a pointer

Posted: Thu Oct 08, 2009 1:54 pm

Hi.

I have declared

Code:

signed int16 Temp[4];

Then,

Code:

for (numRoms=1;numRoms<=4;numRoms++)
{
if (Send_MatchRom())
{
write_byte(0xBE); // Read scratch pad command
dowcrc = 0; // Reset the crc to start a new calculation

for (i=0;i<=7;i++)
{
scratch[i] = read_byte();
ow_crc(scratch[i]); // Accumulate the crc
}

scratch[8] = read_byte(); // Received crc byte
ow_reset();

// If calculated crc from incoming bytes equal to crc byte
// then data is valid. Calculate and output temperature.

if (scratch[8] == dowcrc)
{
            temp = make16(scratch[1],scratch[0]);
            result = (float) temp / 16.0; //0.1 deg C resolution
            //printf(lcd_putc,"\fT%i= %3.1f \uC", numRoms, result);
            Temp[numRoms] = result;
}
else
         {
            printf(lcd_putc,"\fData error."); // There was an error in the data
            delay_ms(1000);
         }
}
}

I want to assign a value to Temp[0], Temp[1], Temp[2], Temp[3],
and then to print this value to LCD.

Code:

printf(lcd_putc, "\nENG:\%3.1fC \EXT:%2.1fC", Temp[0], Temp[1]);

I get 2 errors:

Quote:

** Error 116 "C:\Car_LCD\CarLCD.c" Line 570(62,63): Printf variable count (%) does not match actual count ::
*** Error 66 "C:\Car_LCD\CarLCD.c" Line 638(6,13): Previous identifier must be a pointer

First error I get it from this line:

Code:

printf(lcd_putc, "\nENG:\%3.1fC \EXT:%2.1fC", Temp[0], Temp[1]);

The second error:

Code:

Temp[numRoms] = result;

What is wrong in my code?

PCM programmer

Joined: 06 Sep 2003
Posts: 21708

Posted: Thu Oct 08, 2009 2:14 pm

Quote:

signed int16 Temp[4];
printf(lcd_putc, "\nENG:\%3.1fC \EXT:%2.1fC", Temp[0], Temp[1]);

Look at your code. You have an array of 'signed int' values, but you're
trying to display them as floating point numbers.

Quote:

Temp[numRoms] = result;

You didn't post the declarations for 'numRoms' or 'result'.

It's easier to give you an answer if you post a real test program,
with all varible declarations, and that is compilable. Also post
your PIC and compiler version.

Wayne_

Joined: 10 Oct 2007
Posts: 681


Posted: Fri Oct 09, 2009 1:59 am

Surely the problem lies with the fact the '\' is an escape char i.e \% will escape the % If your intention is to disply a '\' then you need to use 2 off them but I suspect you have just made a mistake! :- printf(lcd_putc, "\nENG: %3.1fC EXT:%2.1fC", Temp[0], Temp[1]); But PCM programmer has a valid point.

pyu

Joined: 04 Feb 2009
Posts: 51

Posted: Fri Oct 09, 2009 2:37 am

I had corrected the first error.

Code:

int8 numROMs;
float result=0;

Here is my entire project, after build, I get that single error (Previous identifier must be a pointer):
http://cid-e0cf397449e54fc9.skydrive.live.com/self.aspx/Public/PicKit2/CarLCD/CarLCD.zip

Last edited by pyu on Fri Oct 09, 2009 2:44 am; edited 1 time in total

Wayne_

Joined: 10 Oct 2007
Posts: 681


Posted: Fri Oct 09, 2009 2:44 am

An array has a zero based index in C So signed int16 Temp[4]; gives you Temp[0] to Temp[3] you either need to change your for loop for (numRoms=0;numRoms<=3;numRoms++) or change the assignment. Temp[numRoms - 1] = result; I don't think this is your problem though. post more info, including definitions of vars used.

pyu

Joined: 04 Feb 2009
Posts: 51

Posted: Fri Oct 09, 2009 2:53 am

Wayne_ wrote:

An array has a zero based index in C
or change the assignment.
Temp[numRoms - 1] = result;

I don't think this is your problem though.

I tried

Code:

Temp[numROMs - 1] = result;

, but no succes.

In previous post, I added a zip with my project.
Here is a sample code:

Code:

int8 numROMs;
float Temp[4];

void Read_DS_Temperature(void)
{
int8 i;
signed int16 temperature;
int8 scratch[9];
signed int16 temp;
float result=0;

if (!ow_reset()) // If a device is present
{
write_byte(0xCC); // Skip Rom command
write_byte(0x44); // Temperature convert command
output_float(DQ);
delay_ms(750); // Max. conv. time is 750mS for 12 bit
ow_reset();

// Now get the device raw temperature data using Match ROM with the
// addresses obtained with FindDevices(). Scale to deg. C, scaling is
// 0.0625 (1/16) deg. C/bit with default 12 bit res. Could reduce res.
// and therefore shorten conversion time if necessary.
// Output the temperatures in whole degrees, apply rounding by adding
// half denom.

for (numROMs=1;numROMs<=4;numROMs++)
{
if (Send_MatchRom())
{
write_byte(0xBE); // Read scratch pad command
dowcrc = 0; // Reset the crc to start a new calculation

for (i=0;i<=7;i++)
{
scratch[i] = read_byte();
ow_crc(scratch[i]); // Accumulate the crc
}

scratch[8] = read_byte(); // Received crc byte
ow_reset();

// If calculated crc from incoming bytes equal to crc byte
// then data is valid. Calculate and output temperature.

if (scratch[8] == dowcrc)
{
            temp = make16(scratch[1],scratch[0]);
            result = (float) temp / 16.0; //0.1 deg C resolution
            //printf(lcd_putc,"\fT%i= %3.1f \uC", numRoms, result);
            Temp[numROMs - 1] = result;
}
else
         {
            printf(lcd_putc,"\fData error."); // There was an error in the data
            delay_ms(1000);
         }
}
}

}
   else
   {
      printf(lcd_putc,"\fSenzor Error!");
      delay_ms(1000);
   }
}

then:
while(1){
printf(lcd_putc, "\nENG:\%3.1fC \EXT:%2.1fC", Temp[0], Temp[1]);
}

Wayne_

Joined: 10 Oct 2007
Posts: 681


Posted: Fri Oct 09, 2009 3:33 am

So which error are you still getting and what is the line ? please show code surrounding this and any definitions as well.

pyu

Joined: 04 Feb 2009
Posts: 51

Posted: Fri Oct 09, 2009 3:41 am

Error:

Code:

*** Error 66 "C:\Car_LCD\CarLCD.c" Line 638(6,13): Previous identifier must be a pointer

Line:

Code:

Temp[numROMs - 1] = result;

main.c:

Code:

#include <16F887.H>
#include <math.h>

#fuses HS,NOWDT,NOLVP,PUT,NOPROTECT,NOBROWNOUT,NOWRT

#use delay(clock = 20000000)

//#device adc=10 *=16 - ???
#define DQ PIN_E0 // One Wire Bus pin assignment

#define RTC_SDA PIN_C4
#define RTC_SCL PIN_C3

#use I2C(MULTI_MASTER,sda=RTC_SDA, scl=RTC_SCL)

#include "Flex_LCD420.c"

#include "CarLCD.h"
#include "CarLCD.c"

void main(void)
{

lcd_init();

output_float(DQ); // Set as input. 4k7 pullup on bus.
FindDevices();
ow_reset();

while(1)
{
DisplayInformations();
}
}

CarLCD.h:

Code:

// Global variables
int8 Rom_Bit[8]; // Rom_Bit bit
int8 lastDiscrep = 0;
short doneFlag = 0;
int8 FoundROM[7][8]; // Table of found ROM codes, 8 bytes for each
int8 numROMs;
int8 dowcrc; // crc is accumulated in this variable

// crc lookup table
int8 const dscrc_table[] = {
0,94,188,226,97,63,221,131,194,156,126,32,163,253,31,65,
157,195,33,127,252,162,64,30,95,1,227,189,62,96,130,220,
35,125,159,193,66,28,254,160,225,191,93,3,128,222,60,98,
190,224,2,92,223,129,99,61,124,34,192,158,29,67,161,255,
70,24,250,164,39,121,155,197,132,218,56,102,229,187,89,7,
219,133,103,57,186,228,6,88,25,71,165,251,120,38,196,154,
101,59,217,135,4,90,184,230,167,249,27,69,198,152,122,36,
248,166,68,26,153,199,37,123,58,100,134,216,91,5,231,185,
140,210,48,110,237,179,81,15,78,16,242,172,47,113,147,205,
17,79,173,243,112,46,204,146,211,141,111,49,178,236,14,80,
175,241,19,77,206,144,114,44,109,51,209,143,12,82,176,238,
50,108,142,208,83,13,239,177,240,174,76,18,145,207,45,115,
202,148,118,40,171,245,23,73,8,86,180,234,105,55,213,139,
87,9,235,181,54,104,138,212,149,203,41,119,244,170,72,22,
233,183,85,11,136,214,52,106,43,117,151,201,74,20,246,168,
116,42,200,150,21,75,169,247,182,232,10,84,215,137,107,53
};

// Returns 0 for one wire device presence, 1 for none
int8 ow_reset(void);

// Read bit on one wire bus
int8 read_bit(void);

void write_bit(int8 bitval) ;

int8 read_byte(void) ;

void write_byte(int8 val) ;

// One wire crc
int8 ow_crc(int8 x) ;

// Searches for the next device on the one wire bus. If there are no more
// devices on the bus then false is returned.
int8 Next(void);

// Resets current state of a ROM search and calls Next to find the first device
// on the one wire bus.
int8 First(void);

void FindDevices(void);

// Sends Match ROM command to bus then device address
int8 Send_MatchRom(void);

float Temp[4];

CarLCD.c:

Code:

//DS18B20

// Returns 0 for one wire device presence, 1 for none
int8 ow_reset(void)
{
int8 presence;

output_low(DQ);
delay_us(488); // Min. 480uS
output_float(DQ);
delay_us(72); // Takes 15 to 60uS for devices to respond
presence = input(DQ);
delay_us(424); // Wait for end of timeslot

//printf(lcd_putc, "\fPresence= %i", presence);

//delay_ms(500);
return(presence);
}

/******************************************************************************/
// Read bit on one wire bus
int8 read_bit(void)
{
output_low(DQ);
delay_us(1); // 1uS min. Original code relied on 8051 being slow
output_float(DQ);
delay_us(20); // Wait at least 15mS from start of time slot

return(input(DQ)); // Delay to finish time slot (total 60 to 120uS)
} // must be done next.

/******************************************************************************/
void write_bit(int8 bitval)
{
output_low(DQ);

if(bitval == 1) {
delay_us(1); // 1uS min. Original code relied on 8051 being slow
output_float(DQ);
}
delay_us(105); // Wait for end of timeslot

output_float(DQ);
}

/******************************************************************************/
int8 read_byte(void)
{
int8 i;
int8 val = 0;

for(i=0;i<8;i++)
{
if(read_bit()) val |= (0x01 << i);
delay_us(120); // To finish time slot
}

return val;
}

/******************************************************************************/
void write_byte(int8 val)
{
int8 i;
int8 temp;

for (i=0;i<8;i++)
{
temp = val >> i;
temp &= 0x01;
write_bit(temp);
}

delay_us(105);
}

/******************************************************************************/
// One wire crc
int8 ow_crc(int8 x)
{
dowcrc = dscrc_table[dowcrc^x];

return dowcrc;
}

/******************************************************************************/
// Searches for the next device on the one wire bus. If there are no more
// devices on the bus then false is returned.
int8 Next(void)
{
int8 m = 1; // ROM Bit index
int8 n = 0; // ROM Byte index
int8 k = 1; // Bit mask
int8 x = 0;
int8 discrepMarker = 0;
int8 g; // Output bit
int8 nxt; // Return value
short flag;

nxt = FALSE; // Reset next flag to false

dowcrc = 0; // Reset the dowcrc

flag = ow_reset();

if (flag||doneFlag) // If no parts return false
{
lastDiscrep = 0; // Reset the search
return FALSE;
}

write_byte(0xF0); // Send SearchROM command

do
{
x = 0;
if (read_bit() == 1)
   x = 2;
delay_us(120);
if (read_bit() == 1)
   x |= 1; // And it's complement

if (x == 3) // There are no devices on the one wire bus
break;
else
{
if (x > 0) // All devices coupled have 0 or 1
g = x >> 1; // Bit write value for search

// If this discrepancy is before the last discrepancy on a previous
// Next then pick the same as last time.
else
{
if (m < lastDiscrep)
g = ((Rom_Bit[n] & k) > 0);
// If equal to last pick 1
else
g = (m == lastDiscrep); // If not then pick 0

// If 0 was picked then record position with mask k
if (g == 0) discrepMarker = m;
}

// Isolate bit in Rom_Bit[n] with mask k
if (g == 1)
      Rom_Bit[n] |= k;
else
      Rom_Bit[n] &= ~k;

write_bit(g); // ROM search write

m++; // Increment bit counter m
k = k << 1; // and shift the bit mask k
// If the mask is 0 then go to new ROM
if (k == 0)
{ // Byte n and reset mask
ow_crc(Rom_Bit[n]); // Accumulate the crc
n++;
k++;
}
}
} while (n < 8); // Loop through until through all ROM bytes 0-7

if (m < (65||dowcrc)) // If search was unsuccessful then
lastDiscrep = 0; // reset the last Discrepancy to zero

else // Search was successful, so set lastDiscrep, lastOne, nxt
{
lastDiscrep = discrepMarker;
doneFlag = (lastDiscrep == 0);
nxt = TRUE; // Indicates search not yet complete, more parts remain
}

return nxt;
}

/******************************************************************************/
// Resets current state of a ROM search and calls Next to find the first device
// on the one wire bus.
int8 First(void)
{
lastDiscrep = 0;
doneFlag = FALSE;

return Next(); // Call Next and return it's return value;
}

/******************************************************************************/
void FindDevices(void)
{
int8 m;
if(!ow_reset())
{
if(First()) // Begins when at least one part found
{
numROMs = 0;

do
{
numROMs++;

for (m=0;m<8;m++)
{
FoundROM[numROMs][m] = Rom_Bit[m]; // Identifies ROM no. on device
}

//printf("Device No.%u address ",numROMs);
      //printf(lcd_putc,"%u no dev=",numROMs);
      //delay_ms(1000);

      printf(lcd_putc, "\f%X%X%X%X%X%X%X%X",
      FoundROM[numROMs][7],FoundROM[numROMs][6],FoundROM[numROMs][5], \
      FoundROM[numROMs][4],FoundROM[numROMs][3],FoundROM[numROMs][2], \
      FoundROM[numROMs][1],FoundROM[numROMs][0]);

      delay_ms(1000);

//printf("%X%X%X%X%X%X%X%X\n\r",
//FoundROM[numROMs][7],FoundROM[numROMs][6],FoundROM[numROMs][5],
//FoundROM[numROMs][4],FoundROM[numROMs][3],FoundROM[numROMs][2],
//FoundROM[numROMs][1],FoundROM[numROMs][0]);


} while (Next() && (numROMs<10)); // Continues until no additional
// devices found.
}
   else
      {
         printf(lcd_putc, "\fno ROM found");
      //delay_ms(500);
      }
}
else
      {
         printf(lcd_putc, "\fno ROM found2");
      //delay_ms(500);
      }
//putc('\n'); putc('\r');
}

/******************************************************************************/
// Sends Match ROM command to bus then device address
int8 Send_MatchRom(void)
{
int8 i;
if (ow_reset()) return FALSE; // 0 if device present
write_byte(0x55); // Match ROM

for (i=0;i<8;i++)
{
write_byte(FoundRom[numROMs][i]); // Send ROM code
}

return TRUE;
}
/******************************************************************************/

void DisplayInformations(void)
{


      Read_DS_Temperature();


      printf(lcd_putc, "\nENG:\%3.1fC \EXT:%2.1fC", Temp[0], Temp[1]);



}

void Read_DS_Temperature(void)
{
int8 i;
signed int16 temperature;
int8 scratch[9];
signed int16 temp;
float result=0;

if (!ow_reset()) // If a device is present
{
write_byte(0xCC); // Skip Rom command
write_byte(0x44); // Temperature convert command
output_float(DQ);
delay_ms(750); // Max. conv. time is 750mS for 12 bit
ow_reset();

// Now get the device raw temperature data using Match ROM with the
// addresses obtained with FindDevices(). Scale to deg. C, scaling is
// 0.0625 (1/16) deg. C/bit with default 12 bit res. Could reduce res.
// and therefore shorten conversion time if necessary.
// Output the temperatures in whole degrees, apply rounding by adding
// half denom.

for (numROMs=1;numROMs<=4;numROMs++)
{
if (Send_MatchRom())
{
write_byte(0xBE); // Read scratch pad command
dowcrc = 0; // Reset the crc to start a new calculation

for (i=0;i<=7;i++)
{
scratch[i] = read_byte();
ow_crc(scratch[i]); // Accumulate the crc
}

scratch[8] = read_byte(); // Received crc byte
ow_reset();

// If calculated crc from incoming bytes equal to crc byte
// then data is valid. Calculate and output temperature.

if (scratch[8] == dowcrc)
{
            temp = make16(scratch[1],scratch[0]);
            result = (float) temp / 16.0; //0.1 deg C resolution
            //printf(lcd_putc,"\fT%i= %3.1f \uC", numRoms, result);
            Temp[numROMs - 1] = result;
}
else
         {
            printf(lcd_putc,"\fData error."); // There was an error in the data
            delay_ms(1000);
         }
}
}

}
   else
   {
      printf(lcd_putc,"\fSenzor Error!");
      delay_ms(1000);
   }
}

FvM

Joined: 27 Aug 2008
Posts: 2337
Location: Germany

Posted: Fri Oct 09, 2009 4:11 am

It's a simple matter of code confusion.

On one hand you're utilizing the default case insensitive behaviour of CCS C (you get many errors, when activating #case for you code), on the other hand you have this:

Code:

int16 temp;
// and at another place
float Temp[4];

Decide, if you are going for #case or #nocase and correct your code respectively.

pyu

Joined: 04 Feb 2009
Posts: 51


Posted: Mon Oct 12, 2009 3:55 am

Thanks FvM. It's working now!

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