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bug I2C PCD

 
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john2003
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bug I2C PCD
PostPosted: Sun May 17, 2009 9:30 pm     Reply with quote
I use dspic30f4012 pcd 4.088
Code:
void ds1307_get_time(BYTE &hr, BYTE &min, BYTE &sec)
{
  i2c_start();
  i2c_write(0xD0);
  i2c_write(0x00);           
  i2c_start();
  i2c_write(0xD1);
  sec = bcd2bin(i2c_read() & 0x7f);  //read data is 0x00 always. no change.
  min = bcd2bin(i2c_read() & 0x7f);  //read data ok. change every minute.
  hr  = bcd2bin(i2c_read(0) & 0x3f); //read data ok. change every hour.
  i2c_stop();
}

void ds1307_get_date(BYTE &day, BYTE &mth, BYTE &year, BYTE &dow)
{
  i2c_start();
  i2c_write(0xD0);
  i2c_write(0x03);            // Start at REG 3 - Day of week
  i2c_start();
  i2c_write(0xD1);
  dow  = bcd2bin(i2c_read() & 0x7f);   //read data ok
  day  = bcd2bin(i2c_read() & 0x3f);   //read data ok
  mth  = bcd2bin(i2c_read() & 0x1f);   //read data ok
  year = bcd2bin(i2c_read(0));           //read data ok
  i2c_stop();
}
john2003
Guest
PostPosted: Sun May 17, 2009 9:41 pm     Reply with quote
but this code i use 16f876 no problem.
ckielstra



Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands

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PostPosted: Mon May 18, 2009 1:22 am     Reply with quote
It helps if you say what your problem is...

Also, the code is incomplete. Post a very small program demonstrating your problem. The program must be complete including fuses, etc., so it can be copy/pasted without changes.
Ttelmah
Guest
PostPosted: Mon May 18, 2009 3:38 am     Reply with quote
One 'obvious' thing would be the clock rate, and speed settings for the I2C bus. I'd guess that you are likely to be clocking the DSPic a lot faster than the 876, and unless you are explicity selecting 100K I2C, the bus may well be too fast for the chip....
A 'mini' program, that just shows the fault, so other people can compile it, and see what is wrong, is the only way to really go.

Best Wishes
john2003
Guest
PostPosted: Mon May 18, 2009 3:58 am     Reply with quote
Code:
// I can not read second. data second is 0x00 alway not change.
// but I can read minute and hour.
#include <30f4012.h>
#use delay(clock=32M,restart_wdt)
#fuses XT_PLL8,PROTECT,NOWDT,NOWRT,NOCKSFSM,CKSNOFSM,NODEBUG,NOCOE
#use rs232(baud=9600,UART1A,ENABLE=PIN_D1)

#define RTC_SDA  PIN_F2
#define RTC_SCL  PIN_F3

#use i2c(master, sda=RTC_SDA, scl=RTC_SCL)

BYTE bin2bcd(BYTE binary_value);
BYTE bcd2bin(BYTE bcd_value);

unsigned int8 hr,min,sec,min_buf,sec_buf;

void ds1307_init(void)
{
   BYTE seconds = 0;

   i2c_start();
   i2c_write(0xD0);      // WR to RTC
   i2c_write(0x00);      // REG 0
   i2c_start();
   i2c_write(0xD1);      // RD from RTC
   seconds = bcd2bin(i2c_read(0)); // Read current "seconds" in DS1307
   i2c_stop();
   seconds &= 0x7F;

   delay_us(3);

   i2c_start();
   i2c_write(0xD0);      // WR to RTC
   i2c_write(0x00);      // REG 0
   i2c_write(bin2bcd(seconds));     // Start oscillator with current "seconds value
   i2c_start();
   i2c_write(0xD0);      // WR to RTC
   i2c_write(0x07);      // Control Register
   i2c_write(0x80);     // Disable squarewave output pin
   i2c_stop();

}

void ds1307_get_time(BYTE &hr, BYTE &min, BYTE &sec)
{
  i2c_start();
  i2c_write(0xD0);
  i2c_write(0x00);            // Start at REG 0 - Seconds
  i2c_start();
  i2c_write(0xD1);
  sec = bcd2bin(i2c_read() & 0x7f);     // REG 0
  min = bcd2bin(i2c_read() & 0x7f);     // REG 1
  hr  = bcd2bin(i2c_read(0) & 0x3f);     // REG 2
  i2c_stop();
}

BYTE bin2bcd(BYTE binary_value)
{
  BYTE temp;
  BYTE retval;

  temp = binary_value;
  retval = 0;

  while(true)
  {
    // Get the tens digit by doing multiple subtraction
    // of 10 from the binary value.
    if(temp >= 10)
    {
      temp -= 10;
      retval += 0x10;
    }
    else // Get the ones digit by adding the remainder.
    {
      retval += temp;
      break;
    }
  }

  return(retval);
}

// Input range - 00 to 99.
BYTE bcd2bin(BYTE bcd_value)
{
  BYTE temp;

  temp = bcd_value;
  // Shifting upper digit right by 1 is same as multiplying by 8.
  temp >>= 1;
  // Isolate the bits for the upper digit.
  temp &= 0x78;

  // Now return: (Tens * 8) + (Tens * 2) + Ones

  return(temp + (temp >> 2) + (bcd_value & 0x0f));
}

void main() {
  ds1307_init();
  while(true){
    ds1307_get_time(hr,min,sec);
    if(sec_buf!=sec){
      sec_buf=sec;
      printf("%X:%X:%X"hr,min,sec);
    }
    if(min_buf!=min){
      sec_buf=min;
      printf("%X:%X:%X"hr,min,sec);
    }
  }
}
john2003
Guest
PostPosted: Mon May 18, 2009 4:04 am     Reply with quote
Code:
#include <30f4012.h>
#use delay(clock=32M,restart_wdt)
#fuses XT_PLL8,PROTECT,NOWDT,NOWRT,NOCKSFSM,CKSNOFSM,NODEBUG,NOCOE
#use rs232(baud=9600,UART1A,ENABLE=PIN_D1)

#define RTC_SDA  PIN_F2
#define RTC_SCL  PIN_F3

#use i2c(master, sda=RTC_SDA, scl=RTC_SCL)

BYTE bin2bcd(BYTE binary_value);
BYTE bcd2bin(BYTE bcd_value);

unsigned int8 hr,min,sec,min_buf,sec_buf;

void ds1307_init(void)
{
   BYTE seconds = 0;

   i2c_start();
   i2c_write(0xD0);      // WR to RTC
   i2c_write(0x00);      // REG 0
   i2c_start();
   i2c_write(0xD1);      // RD from RTC
   seconds = bcd2bin(i2c_read(0)); // Read current "seconds" in DS1307
   i2c_stop();
   seconds &= 0x7F;

   delay_us(3);

   i2c_start();
   i2c_write(0xD0);      // WR to RTC
   i2c_write(0x00);      // REG 0
   i2c_write(bin2bcd(seconds));     // Start oscillator with current "seconds value
   i2c_start();
   i2c_write(0xD0);      // WR to RTC
   i2c_write(0x07);      // Control Register
   i2c_write(0x80);     // Disable squarewave output pin
   i2c_stop();

}

void ds1307_get_time(BYTE &hr, BYTE &min, BYTE &sec)
{
  i2c_start();
  i2c_write(0xD0);
  i2c_write(0x00);            // Start at REG 0 - Seconds
  i2c_start();
  i2c_write(0xD1);
  sec = bcd2bin(i2c_read() & 0x7f);     // REG 0
  min = bcd2bin(i2c_read() & 0x7f);     // REG 1
  hr  = bcd2bin(i2c_read(0) & 0x3f);     // REG 2
  i2c_stop();
}

BYTE bin2bcd(BYTE binary_value)
{
  BYTE temp;
  BYTE retval;

  temp = binary_value;
  retval = 0;

  while(true)
  {
    // Get the tens digit by doing multiple subtraction
    // of 10 from the binary value.
    if(temp >= 10)
    {
      temp -= 10;
      retval += 0x10;
    }
    else // Get the ones digit by adding the remainder.
    {
      retval += temp;
      break;
    }
  }

  return(retval);
}

// Input range - 00 to 99.
BYTE bcd2bin(BYTE bcd_value)
{
  BYTE temp;

  temp = bcd_value;
  // Shifting upper digit right by 1 is same as multiplying by 8.
  temp >>= 1;
  // Isolate the bits for the upper digit.
  temp &= 0x78;

  // Now return: (Tens * 8) + (Tens * 2) + Ones

  return(temp + (temp >> 2) + (bcd_value & 0x0f));
}

void main() {
  ds1307_init();
  while(true){
    ds1307_get_time(hr,min,sec);
    if(sec_buf!=sec){
      sec_buf=sec;
      printf("%X:%X:%X"hr,min,sec);
    }
    if(min_buf!=min){
      min_buf=min;
      printf("%X:%X:%X"hr,min,sec);
    }
  }
}
Ttelmah
Guest
PostPosted: Mon May 18, 2009 4:17 am     Reply with quote
So try specifying a clock rate for the I2C:

#use i2c(master, sda=RTC_SDA, scl=RTC_SCL, SLOW)

Best Wishes
john2003
Guest
PostPosted: Mon May 18, 2009 4:33 am     Reply with quote
// not work

#use i2c(master, sda=RTC_SDA, scl=RTC_SCL, SLOW)
FvM



Joined: 27 Aug 2008
Posts: 2337
Location: Germany

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PostPosted: Mon May 18, 2009 3:20 pm     Reply with quote
I tried your last code version on a PIC24FJ128GA106 with a DS1337 RTC connected and it did display seconds as expected.

But I found a PCD bug with I2CBRG setup. For a clock frequency of 32 MHz, it should be set to 0x0122. Unfortunately, only an 8-Bit value is set. The programmer seems to have forgotten, that he's dealing with a 16-Bit processor.
Code:
  02C6  B3C220     mov.b #0x22,0x0000
  02C8  B7E204     mov.b 0x0000,0x0204

The erroneous setting results in about 850 kHz I2C clock.
Set I2CBRG manually in your code as a workaround.
Code:
#word I2CBRG = 0x204
I2CBRG = 0x122;

Best regards,
Frank
john2003
Guest
PostPosted: Mon May 18, 2009 11:26 pm     Reply with quote
Why i can read hour and minute. but i can not read second.
FvM



Joined: 27 Aug 2008
Posts: 2337
Location: Germany

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PostPosted: Tue May 19, 2009 12:02 am     Reply with quote
Don't know. It may be related to the wrong frequency. Don't ask, please try.

I used most recent PCD V4.092. I didn't check for possible additional bugs with V4.088 or special
issues with dsPIC30 code. However, PIC24 I2C code has been operational for me since V4.079.
Because my application has a 16 MHz clock, I wasn't aware of the said bug.
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