CCS C Software and Maintenance Offers
FAQFAQ   FAQForum Help   FAQOfficial CCS Support   SearchSearch  RegisterRegister 

ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

CCS does not monitor this forum on a regular basis.

Please do not post bug reports on this forum. Send them to CCS Technical Support

Did anyone work with Seiko RTCs?

 
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion
View previous topic :: View next topic  
Author Message
KaraMuraT



Joined: 16 May 2006
Posts: 65
Location: Ankara/Turkey

View user's profile Send private message Send e-mail

Did anyone work with Seiko RTCs?
PostPosted: Fri Feb 16, 2007 12:56 am     Reply with quote

Hi,

I'm using Seiko S35390A Real Time Clock in the new project. This one is the lowest power RTC I know. (Typical: 250nA @3.3V, 400nA @5V).

But I have problems with it. I can access via I2C, set registers and read them back properly, except real time data register. And as you can guess the most important register.

Whether I set it or not, I get same garbage data. Have anyone worked with Seiko RTCs?

Let me paste the code here...

P.S: You'll see a ReverseInt function, which is not normal in I2C communcations. Unfortunately Seiko sends and receives LSB first, not the MSB. That's why I used this function.

P.S.2: Datasheet address if required: ftp://ftp.sii.co.jp/pub/ic/speed_dt/dt_sht_e/assp/S35390A_E.pdf

Code:


#use i2c(MASTER, SCL=PIN_C3,SDA=PIN_C4, SLOW, FORCE_HW)

#define RTC_IC           0x60                 /// Fixed Seiko S35390A I2C address start
 

#define REG_STAT_1       0x00                 /// All values 1 bit shifted to left
#define REG_STAT_2       0x02
#define RTC_DATA_1       0x04
#define RTC_DATA_2       0x06
#define REG_INT_1        0x08
#define REG_INT_2        0x0A
#define REG_CLK_ADJ      0x0C
#define REG_FREE         0x0E
 
#define I2C_WR           0x00
#define I2C_RD           0x01


unsigned int ReverseInt(unsigned int value)
{
   unsigned int reversed;
   unsigned int rc;      /// just a counter
   
   for(rc=0;rc<8;rc++)
   {
      if(bit_test(value, rc))    bit_set(reversed, 7 - rc);
   }
   
   return reversed;

}

 
void RTCSetDateTime()
{
    MtrDateTime.yr       = ReverseInt(MtrDateTime.yr);
    MtrDateTime.mth      = ReverseInt(MtrDateTime.mth);
    MtrDateTime.day      = ReverseInt(MtrDateTime.day);
    DayOfWeekNow         = ReverseInt(DayOfWeekNow);
    MtrDateTime.hr       = ReverseInt(MtrDateTime.hr);
    MtrDateTime.min      = ReverseInt(MtrDateTime.min);
    SecondsNow           = ReverseInt(SecondsNow);
           
    i2c_start();
    i2c_write(RTC_IC | RTC_DATA_1 | I2C_WR);      ///Accessing to Real Time Data Register.
    i2c_write(MtrDateTime.yr);
    i2c_write(MtrDateTime.mth);
    i2c_write(MtrDateTime.day);
    i2c_write(DayOfWeekNow);
    i2c_write(MtrDateTime.hr);
    i2c_write(MtrDateTime.min);
    i2c_write(0x00);                              /// set seconds to zero
    i2c_stop();
           
}
 
void RTCReadDateTime()
{
    ///Accessing to Real Time Data Register
           
   i2c_start();
    i2c_write(RTC_IC | RTC_DATA_1 | I2C_RD);
    MtrDateTime.yr        = i2c_read();
    MtrDateTime.mth       = i2c_read();
    MtrDateTime.day       = i2c_read();
    DayOfWeekNow          = i2c_read();
    MtrDateTime.hr        = i2c_read();
    MtrDateTime.min       = i2c_read();
    SecondsNow            = i2c_read(0);                                                                         
    i2c_stop();
 
    /// Reverse the incoming Data (explained at page top)
    MtrDateTime.yr        = ReverseInt(MtrDateTime.yr);
    MtrDateTime.mth       = ReverseInt(MtrDateTime.mth);
    MtrDateTime.day       = ReverseInt(MtrDateTime.day);
    DayOfWeekNow          = ReverseInt(DayOfWeekNow);
    MtrDateTime.hr        = ReverseInt(MtrDateTime.hr);
    MtrDateTime.min       = ReverseInt(MtrDateTime.min);
    SecondsNow            = ReverseInt(SecondsNow);
           
    /// Mask necessary values
    MtrDateTime.mth       &= 0b00011111;
    MtrDateTime.day       &= 0b00111111;
    DayOfWeekNow          &= 0b00000111;
    MtrDateTime.hr        &= 0b00111111;
    MtrDateTime.min       &= 0b01111111;
    SecondsNow            &= 0b01111111;

}


_________________
/// KMT
/// www.muratursavas.com
ckielstra



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

View user's profile Send private message

PostPosted: Fri Feb 16, 2007 9:58 am     Reply with quote

The ReverseInt() function has a bug; you are only setting bit values when they are '1', not clearing any values. This will only work when the start value of 'reversed' is initialized to zero.

Change
Code:
   unsigned int reversed;
to
Code:
   unsigned int reversed = 0;
ckielstra



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

View user's profile Send private message

PostPosted: Fri Feb 16, 2007 12:27 pm     Reply with quote

You might want to have a look at http://www.ccsinfo.com/forum/viewtopic.php?p=76547 where I just placed a comparison of several bit-order reverse routines. Your routine uses an average of 374 instruction cycles while the fastest routine published there can achieve the same result in just 24 instruction cycles.
KaraMuraT



Joined: 16 May 2006
Posts: 65
Location: Ankara/Turkey

View user's profile Send private message Send e-mail

PostPosted: Sat Feb 17, 2007 11:41 am     Reply with quote

Thank you ckielstra,

The routine was not really checked. It was written for a quick test after the response of a Seiko Engineer.

I was planning to rewrite it after solving the I2C data acqusition problem, but you helped me to process it faster. Thank you.

Also do you got any idea about this I2C problem?. you may never used seiko RTC but I'm open for any thoughts. Because I've ran out of ideas...
_________________
/// KMT
/// www.muratursavas.com
Kenny



Joined: 07 Sep 2003
Posts: 173
Location: Australia

View user's profile Send private message

PostPosted: Sun Feb 18, 2007 4:42 pm     Reply with quote

If you can read and write to other registers successfully, then there
is probably no i2c problem.

For testing, try reading the raw data without reversing the bit order
or masking the data bits. See if the data makes sense keeping in mind
that the data is in packed bcd format, not binary, and the bits are in reverse order.

BTW the Philips PCF8563 is an RTC that consumes about the same current


Last edited by Kenny on Mon Feb 19, 2007 8:58 am; edited 1 time in total
KaraMuraT



Joined: 16 May 2006
Posts: 65
Location: Ankara/Turkey

View user's profile Send private message Send e-mail

PostPosted: Mon Feb 19, 2007 12:34 am     Reply with quote

Thanks for the heads up Kenny. I totally forgot about PCF8563. Think that it has higher consumption. I got samples and try it today.

Tha data "was" making sense. It was working after reset and increased the time starting to this value: 00 01 01 01 01 01.

But I never had a chance to set it to an another time. If I try it just turns to meaningless time. For example the data must be in BCD format, and returns like 3F. But maybe the reversing function is not right. That's why its not functioning well.

I'll try the PCF8563, and if it works fine, I'll never look back to seiko as RTC. (But I recommend to use their voltage regulators due to low power consumption)
_________________
/// KMT
/// www.muratursavas.com
ckielstra



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

View user's profile Send private message

PostPosted: Mon Feb 19, 2007 2:13 am     Reply with quote

Quote:
But maybe the reversing function is not right. That's why its not functioning well.
I had a look at your program and at the RTC datasheet; I agree with Kenny that it is very likely your problem is not I2C related.
Have you tried my correction to your reverse function? Without the fix you will send to and receive garbage data from the RTC.
KaraMuraT



Joined: 16 May 2006
Posts: 65
Location: Ankara/Turkey

View user's profile Send private message Send e-mail

PostPosted: Mon Feb 19, 2007 3:00 am     Reply with quote

I just tried NXP PCF8563 it and works fine with 1/100 effort comparing Seiko S35390A. Now Seiko RTC is history for me.... Welcome PCF8563 Smile

I'll test it later in a spare time with Seiko, and inform you. Just removed the IC and don't want to waste time with resoldering. I'm really running out of time.
_________________
/// KMT
/// www.muratursavas.com
KaraMuraT



Joined: 16 May 2006
Posts: 65
Location: Ankara/Turkey

View user's profile Send private message Send e-mail

PostPosted: Tue Feb 20, 2007 12:27 am     Reply with quote

And let me aware you something about seiko rtc. if you try to get the time in every second it does not answer you. Needs at least 2 seconds between communication. Is it normal? No... I didn't expect something like this and still don't. But it behaves so.

With PCF8563, I'm getting the real time data every second, and works just fine...
_________________
/// KMT
/// www.muratursavas.com
PICoHolic



Joined: 04 Jan 2005
Posts: 224

View user's profile Send private message

PostPosted: Tue Feb 20, 2007 7:14 am     Reply with quote

You might give DS1307 a try too Wink
KaraMuraT



Joined: 16 May 2006
Posts: 65
Location: Ankara/Turkey

View user's profile Send private message Send e-mail

PostPosted: Wed Feb 21, 2007 1:58 am     Reply with quote

Thanks for the advice but I'll stick to PCF8563. It has Alarm functions, and countdown timer and square wave output. DS1307 has square wave output and switch circuitry. Our product is battery powered and does not need switch circuitry. And I need alarm functions for non-linear (not periodic) workflow. This minimizes power consumption dramatically.

And also DS1307 is %106 expensive comparing to PCF8563
(0.66 USD / 1.36 USD)
_________________
/// KMT
/// www.muratursavas.com
PICoHolic



Joined: 04 Jan 2005
Posts: 224

View user's profile Send private message

PostPosted: Wed Feb 21, 2007 3:25 am     Reply with quote

10x for the last info Wink
Display posts from previous:   
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion All times are GMT - 6 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group