# expected primary expression before '.' token

**URL:** <https://forum.arduino.cc/t/expected-primary-expression-before-token/44976>\
**Category:** Syntax & Programs\
**Created:** [October 2, 2010, 5:15am UTC](https://forum.arduino.cc/t/expected-primary-expression-before-token/44976 "2010-10-02T05:15:45Z")\
**Posts on this page:** 9\
**Page:** 1

<div class="post-metadata">

**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [October 2, 2010, 5:15am UTC](https://forum.arduino.cc/t/expected-primary-expression-before-token/44976/1 "2010-10-02T05:15:45Z")

</div>

I have copied some Sparkfun code for interfacing a IG3200 gyro with my arduino. When I compile I get an error "expected primary expression before '.' token.

The code following code line gets highlited:  
static FILE mystdout = FDEV\_SETUP\_STREAM(uart\_putchar, NULL, \_FDEV\_SETUP\_WRITE);

Any ideas as to what the error is:

```cpp
   ITG-3200 Test Code
      April 28, 2010
      by: Jim Lindblom
      License: Creative Commons Attribution Share-Alike 3.0
      http://creativecommons.org/licenses/by-sa/3.0
      
      ITG-3200 Triple-axis Digital Output Gyroscope test code. Streams the three axis output of the gyro.
      Provides options to average the readings, and modify the sample rate, DLPF, and power management registers.
      
      Tested on a 3.3V 8MHz Arduino Pro
      10kOhm pull-ups on I2C lines.
      VDD & VIO = 3.3V
      SDA -> A4 (PC4)
      SCL -> A5 (PC5)
      INT -> D2 (PB2) (or no connection, not used here)
      CLK -> GND
*/

#include <stdlib.h>
#include <stdio.h>
#include <avr/io.h>
#include "i2c.h"
#include "itg320.h"

#define FOSC 8000000
#define ITG3200_R 0xD3      // ADD pin is pulled high
#define ITG3200_W 0xD2      // So address is 0x69

#define sbi(var, mask)   ((var) |= (uint8_t)(1 << mask))
#define cbi(var, mask)   ((var) &= (uint8_t)~(1 << mask))

///============Function Prototypes=========/////////////////
char ITG3200Read(unsigned char address);
void ITG3200Write(unsigned char address, unsigned char data);
void ITG3200ViewRegisters(void);
int checkInterrupt(void);
void getITG3200(int average);
void ITG3200BlockRead(unsigned char address);

///============General Use Prototypes=====//////////////////;

void ioinit(void);
void UART_Init(unsigned int ubrr);
static int uart_putchar(char c, FILE *stream);
void put_char(unsigned char byte);
uint8_t uart_getchar(void);
static FILE mystdout = FDEV_SETUP_STREAM(uart_putchar, NULL, _FDEV_SETUP_WRITE);
void delay_ms(uint16_t x);

int main(void)
{
      char temp;
      unsigned int i = 0;
      int average = 1;
      unsigned short sample = 128;
      unsigned short dlpf = 0;
      unsigned char power = 0;
      long int count = 0;
      
      ioinit();
      i2cInit();
      delay_ms(100);
      
      ITG3200Write(PWR_M, 0x80);      // Reset to defaults
      ITG3200Write(SMPL, 0x00);      // SMLPRT_DIV = 0
      ITG3200Write(DLPF, 0x18);      // DLPF_CFG = 0, FS_SEL = 3
      ITG3200Write(INT_C, 0x05);      // Generate interrupt when device is ready or raw data ready
      ITG3200Write(PWR_M, 0x00);
      
      delay_ms(1000);
      
      while(1)
      {
            printf("\nITG-3200 Configuration Menu\n");
            printf("---------------------------\n");
            printf("1) Stream Values\n");
            printf("2) Change average value (currently %d)\n", average);
            printf("3) Change Sample Rate Divider (currently %d)\n", ITG3200Read(SMPL));
            printf("4) Adjust digital low pass filter (currently %d)\n", (ITG3200Read(DLPF)&0x07));
            printf("5) Adjust Power Management Register (currently 0x%x)\n", ITG3200Read(PWR_M));
            printf("6) View all ITG-3200 Registers\n");
            temp = uart_getchar();
            
            if (temp == '1')
            {
                  count = 0;
                  printf("\nStreaming, press any key to stop...\n\n");
                  printf("Count       x       y       z\n");
                  printf("-----      ---      ---      ---\n");
                  while(!(UCSR0A & (1<<RXC0)))
                  {
                        printf("%ld:", count);
                        getITG3200(average);
                        count++;
                  }
                  temp = UDR0;
            }
            else if (temp == '2')
            {
                  i = 0;
                  average = 0;
                  printf("\nType the new average value followed by the enter key...\n");
                  while (1)
                  {
                        temp = uart_getchar();
                        if (temp == 0x0D)
                              break;
                        else if ((temp>=0x30)&&(temp<=0x39))
                        {
                              temp -= 0x30;
                              printf("%d", temp);
                              average *= 10;
                              average += temp;
                              i++;
                        }
                  }
                  printf("\n");
                  if (average == 0) average = 1;
            }
            else if (temp == '3')
            {
                  i = 0;
                  sample = 0;
                  printf("\nType the new sample rate divider (0-255) followed by the enter key...\n");
                  printf("Sample Rate = (8KHz or 1KHz [determined by DLPF])/(divider +1)\n");
                  while (1)
                  {
                        temp = uart_getchar();
                        if (temp == 0x0D)
                              break;
                        else if ((temp>=0x30)&&(temp<=0x39))
                        {
                              temp -= 0x30;
                              printf("%d", temp);
                              sample *= 10;
                              sample += temp;
                              i++;
                        }
                  }
                  ITG3200Write(SMPL, sample);
                  printf("\n");
            }
            else if (temp == '4')
            {
                  printf("\nType the new DLPF value (0-6)...\n");
                  printf("DLPF      LPF-BW      Sample Rate\n");
                  printf("0      256Hz      8kHz\n");
                  printf("1      188Hz      1kHz\n");
                  printf("2      98Hz      1kHz\n");
                  printf("3      42Hz      1kHz\n");
                  printf("4      20Hz      1kHz\n");
                  printf("5      10Hz      1kHz\n");
                  printf("6      5Hz      1kHz\n");
                  while (1)
                  {
                        temp = uart_getchar();
                        if ((temp>=0x30)&&(temp<=0x36))
                        {
                              dlpf = temp - 0x30;
                              break;
                        }
                        else
                              printf("Invalid\n");
                  }
                  temp = 0b00011000 | dlpf;
                  ITG3200Write(DLPF, temp);
            }
            else if (temp == '5')
            {
                  printf("\nEnter a 8-bit hex value...\n");
                  printf("0x");
                  
                  temp = uart_getchar();
                  if ((temp>=0x30)&&(temp<=0x39))
                  {
                        temp -= 0x30;
                        printf("%x", temp);
                  }
                  else if ((temp>=0x41)&&(temp<=0x46))
                  {
                        temp -= 55;
                        printf("%x", temp);
                  }
                  else if ((temp>=0x61)&&(temp<=0x66))
                  {
                        temp -= 87;
                        printf("%x", temp);
                  }
                  else
                  {
                        printf("Invalid\n");
                        temp = 0;
                  }
                  power = temp << 4;
                  
                  temp = uart_getchar();
                  if ((temp>=0x30)&&(temp<=0x39))
                  {
                        temp -= 0x30;
                        printf("%x", temp);
                  }
                  else if ((temp>=0x41)&&(temp<=0x46))
                  {
                        temp -= 55;
                        printf("%x", temp);
                  }
                  else if ((temp>=0x61)&&(temp<=0x66))
                  {
                        temp -= 87;
                        printf("%x", temp);
                  }
                  else
                  {
                        printf("Invalid\n");
                        temp = 0;
                  }
                  temp &= 0x0F;
                  power |= temp;
                  
                  printf("\n");
                  ITG3200Write(PWR_M, power);
            }
            else if (temp == '6')
                  ITG3200ViewRegisters();
      }
}

char ITG3200Read(unsigned char address)
{
      char data;
      
      cbi(TWCR, TWEN);      // Disable TWI
      sbi(TWCR, TWEN);      // Enable TWI
      
      i2cSendStart();
      i2cWaitForComplete();
      
      i2cSendByte(ITG3200_W);      // write 0xD2
      i2cWaitForComplete();
      
      i2cSendByte(address);      // write register address
      i2cWaitForComplete();
      
      i2cSendStart();
      
      i2cSendByte(ITG3200_R);      // write 0xD3
      i2cWaitForComplete();
      i2cReceiveByte(FALSE);
      i2cWaitForComplete();
      
      data = i2cGetReceivedByte();      // Get MSB result
      i2cWaitForComplete();
      i2cSendStop();
      
      cbi(TWCR, TWEN);      // Disable TWI
      sbi(TWCR, TWEN);      // Enable TWI
      
      return data;
}

void ITG3200Write(unsigned char address, unsigned char data)
{
      i2cSendStart();
      i2cWaitForComplete();
      
      i2cSendByte(ITG3200_W);      // write 0xB4
      i2cWaitForComplete();
      
      i2cSendByte(address);      // write register address
      i2cWaitForComplete();
      
      i2cSendByte(data);
      i2cWaitForComplete();
      
      i2cSendStop();
}

void ITG3200ViewRegisters(void)
{
      printf("\nWHO_AM_I (0x00): 0x%x\n", ITG3200Read(WHO));
      delay_ms(1000);
      printf("SMPLRT_DIV (0x15): 0x%x\n", ITG3200Read(SMPL));
      printf("DLPF_FS (0x16): 0x%x\n", ITG3200Read(DLPF));
      printf("INT_CFG (0x17): 0x%x\n", ITG3200Read(INT_C));
      printf("INT_STATUS (0x1A): 0x%x\n", ITG3200Read(INT_S));
      printf("TEMP_OUT_H (0x1B): 0x%x\n", ITG3200Read(TMP_H));
      printf("TEMP_OUT_L (0x1C): 0x%x\n", ITG3200Read(TMP_L));
      printf("GYRO_XOUT_H (0x1D): 0x%x\n", ITG3200Read(GX_H));
      printf("GYRO_XOUT_L (0x1E): 0x%x\n", ITG3200Read(GX_L));
      printf("GYRO_YOUT_H (0x1F): 0x%x\n", ITG3200Read(GY_H));
      printf("GYRO_YOUT_L (0x20): 0x%x\n", ITG3200Read(GY_L));
      printf("GYRO_ZOUT_H (0x21): 0x%x\n", ITG3200Read(GZ_H));
      printf("GYRO_ZOUT_L (0x22): 0x%x\n", ITG3200Read(GZ_L));
      printf("PWR_MGM (0x3E): 0x%x\n", ITG3200Read(PWR_M));
}

int checkInterrupt(void)
{
      if ((PIND & (1<<2)) == 0)
            return 0;
      else
            return 1;
}

void getITG3200(int average)
{
      char temp;
      signed int gx[average], gy[average], gz[average];
      signed int gyrox = 0;
      signed int gyroy = 0;
      signed int gyroz = 0;
      unsigned int i;
      
      for (i = 0; i<average; i++)
      {
            while (!(ITG3200Read(INT_S) & 0x01))
            ;
            temp = 0;
            temp = ITG3200Read(GY_H);
            gy[i] = temp << 8;
            gy[i] |= ITG3200Read(GY_L);

            //while (!(ITG3200Read(INT_S) & 0x01))
            //;
            temp = 0;
            temp = ITG3200Read(GZ_H);
            gz[i] = temp << 8;
            gz[i] |= ITG3200Read(GZ_L);
            
            //while (!(ITG3200Read(INT_S) & 0x01))
            //;
            temp = 0;
            temp = ITG3200Read(GX_H);
            gx[i] = temp << 8;
            gx[i] |= ITG3200Read(GX_L);

            
            gyrox += gx[i];
            gyroy += gy[i];
            gyroz += gz[i];
      }
      
      gyrox = gyrox/average;
      gyroy = gyroy/average;
      gyroz = gyroz/average;
      
      printf("      %d      %d      %d\n", gyrox, gyroy, gyroz);
}

/ *********************
 ****Initialize****
 ********************* /
 
void ioinit (void)
{
    //1 = output, 0 = input
      DDRB = 0b01100000; //PORTB4, B5 output
    DDRC = 0b00010011; //PORTC4 (SDA), PORTC5 (SCL)
    DDRD = 0b11111010; //PORTD (RX on PD0)
      PORTC = 0b00110000; //pullups on the I2C bus
      //sbi(PORTD, 2);
      UART_Init(8);      // U2X0 is set! - 115200bps @ 8MHz
}

void UART_Init(unsigned int ubrr)
{
      // Set baud rate 
      UBRR0H = ubrr>>8;
      UBRR0L = ubrr;
      
      // Enable receiver and transmitter 
      UCSR0A = (1<<U2X0);
      UCSR0B = (1<<RXEN0)|(1<<TXEN0);
      
      // Set frame format: 8 bit, no parity, 1 stop bit,   
      UCSR0C = (1<<UCSZ00)|(1<<UCSZ01);
      
      stdout = &mystdout; //Required for printf init
}

static int uart_putchar(char c, FILE *stream)
{
    if (c == '\n') uart_putchar('\r', stream);
  
    loop_until_bit_is_set(UCSR0

```

---

<div class="post-metadata">

**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [October 2, 2010, 5:18am UTC](https://forum.arduino.cc/t/expected-primary-expression-before-token/44976/2 "2010-10-02T05:18:25Z")

</div>

Sure. There is no file system on the Arduino, so you can't create a FILE object.

Where did you copy this code from? It certainly doesn't look like Arduino code.

---

<div class="post-metadata">

**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [October 2, 2010, 5:30am UTC](https://forum.arduino.cc/t/expected-primary-expression-before-token/44976/3 "2010-10-02T05:30:54Z")

</div>

I copied it from the [sparkfun.com](http://sparkfun.com) site. I guess the code is writing the gyro output to a file. Is there a way around this?

---

<div class="post-metadata">

**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [October 2, 2010, 5:37am UTC](https://forum.arduino.cc/t/expected-primary-expression-before-token/44976/4 "2010-10-02T05:37:20Z")

</div>

> I copied it from the [sparkfun.com](http://sparkfun.com) site.

It's a pretty big site, with lots of code...

> I guess the code is writing the gyro output to a file. Is there a way around this?

Yes. Don't write the data to a file.

---

<div class="post-metadata">

**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [October 2, 2010, 6:00am UTC](https://forum.arduino.cc/t/expected-primary-expression-before-token/44976/5 "2010-10-02T06:00:06Z")

</div>

Yes, ok thanks. Learning the obvious is not immediately apparent 🙂

> **[Triple-Axis Digital-Output Gyro ITG-3200 Breakout - SEN-09801 - SparkFun...](https://www.sparkfun.com/products/retired/9801)**
>
> \*\*Replacement:\*\*\[SEN-11977\](https://www.sparkfun.com/products/11977). We have a new rev of this breakout, go check it out! This page is for reference only.

---

<div class="post-metadata">

**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [October 2, 2010, 2:00pm UTC](https://forum.arduino.cc/t/expected-primary-expression-before-token/44976/6 "2010-10-02T14:00:42Z")

</div>

That whole page seems screwed up. That code contains a main() function. Arduino sketches do not.

The comments talk about how to get correct temperature readings from it. WTF?

There is mention of using it in the AeroQuad project, so it just might be time to hit up google.

---

<div class="post-metadata">

**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [October 2, 2010, 3:03pm UTC](https://forum.arduino.cc/t/expected-primary-expression-before-token/44976/7 "2010-10-02T15:03:19Z")

</div>

That code should compile with 0 errors on AvrStudio, if you dont use it you need to port it to arduino c/c++.  
With the proper coding you can use the FILE to stream data to printf over the serial port to a computer.

---

<div class="post-metadata">

**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [October 2, 2010, 3:26pm UTC](https://forum.arduino.cc/t/expected-primary-expression-before-token/44976/8 "2010-10-02T15:26:46Z")

</div>

Thanks for the help. I am using the gyro in the aeroquad project but wanted to understand how the gyro communicated with the arduino and also to understand the data coming from it - thus my attempt at using the code from sparkfun. A steep learning curve when you are trying to also figure out the programming language - but fun none-the-less. Dont know about avrstudio (yet).

---

<div class="post-metadata">

**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [May 6, 2021, 8:10pm UTC](https://forum.arduino.cc/t/expected-primary-expression-before-token/44976/9 "2021-05-06T20:10:59Z")

</div>